# Feeding both sides of panel with no 240v breakers bridging across.



## bwswede (Sep 13, 2020)

Greetings generator friends,

I have a pair of inverter generators (2400 watts surge each) and I am wondering what risks, dangers, lectures, etc. I will be subject to if I backfeed into my panel with each generator lighting up one side of the panel. The panel is split with all 240v breakers on top including one that feeds the bottom half of the panel which is all 120v breakers. By shutting off the 240 breaker feeding the bottom half of the panel the 120v circuits on each half of the panel of course are separated except where the neutrals are tied together. To be clear, with this scenario I would only be feeding 120v breakers, half with one generator and half with the other.

TIA,
Blane


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## Old man here (Nov 5, 2020)

No, No, and No!
Use extension cords to the appliances you need to run.


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## motormonkey (Jul 10, 2016)

None of your 240 stuff will work with that. And more importantly, you forgot to mention the most important thing if you are doing this: TURN OFF THE MAIN BREAKER. It's waaaay too easy to forget to do that, and if you do, you could electrocute some poor lineman out there up on a pole trying to get your power back on.

Now, if you put a proper interlock between the main breaker and your backfeed breaker that will positively prevent backfeeding to the utility, that's a different story.


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## bwswede (Sep 13, 2020)

Thanks for the replies guys. 

Old man, would you mind explaining your reasoning behind your answers. To the uniformed your answers are very appropriate but I have been back feeding my panel every power outage of any length for the last 30 years and since I am extremely careful I have not had a single incident. I do not run cords into the house as open doors and/or windows creates a security issue.

Motormonkey, I forgot to mention that I do not have a main breaker in the panel. I always pull the meter from the socket when I backfeed the house. I understand that I cannot run anything with 240v and that is okay. Even if I could the little inverter generators are not powerful enough for the water heater or the oven.

I have set up my house with dedicated backfeed circuits to the rear of my house. There is nothing on these lines other than a receptacle at the exterior. I ran #12 wire which will handle more than each generator will produce.

My question is, what is the harm, if there is any, of running a separate generator to each side of the panel when there is no "cross contamination" of the two sides other than where the neutrals tie together. Since the neutrals tie together both sides of the panel when operating with utility power how is what I am proposing to do any different?

Thanks again,
Blane


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## motormonkey (Jul 10, 2016)

Personally, I would not backfeed electricity into my house circuit without a positive interlock in place to eliminate all possibility of energizing the utility line. The consequences of you, (or someone else,) failing to turn the main breaker off or remove the power meter are just too serious.

Also, the neutral and ground conductors in your home's electrical system are bonded together at a single point somewhere in the system. It is not a good idea to have a second bonding point in the system, such as within the generators. Generators commonly come from the factory with these conductors bonded. These bonding jumpers should be easy enough to remove.

Aside from these two issues, there is no harm in doing what you propose.

BTW, how do you get by with removing your power meter? Here, the power company has their seal on the meter box and they get upset if it is disturbed.


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## bwswede (Sep 13, 2020)

Thanks for your reply Motormonkey confirming what I thought but didn't know for sure. My little inverter generators are each a Honda EU2200i. They have a floating neutral so there isn't an issue of having two places where the neutral is bonded to the ground (it will only occur at the main panel).

To answer your question after removing the meter from the socket during a power outage I call the power company up to reseal it after my power is restored. The customer service representative simply asks if I did any work on my electric system when the meter was removed, I say no, and then they tell me they will send out an inspector to reseal the meter. I have been told by a power company lineman that they appreciate when a meter is pulled by a homeowner while they are running a generator. Whether this is a company wide policy or not I don't know.

Thanks again,
Blane


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## iowagold (Jan 22, 2020)

WOW!
yea here in Iowa and Illinois they have strict rules on removing meters.
even as an electrician they want to be the ones doing a pull and re install of the meter here.

if you cut a meter or box tag here the fines start at $500.00 and run up to jail time.
part of that diversion rules they now have....

too many contractors were connecting with a fake meter....

but if you call them and ask for a meter removal or line snip.
now days they have less of a time wait!
i think i was at 1/2 an hour till there were here....
the line man even waited the 15 min for me to complete the tie in jumpers to the new outside disconnect.

I have pad locks on both the meter and the disconnect box now...
they agreed and like the idea!
that way we both have to be there for a removal or shut down of power.
and it keeps meter theft or some one trying to shut down power to the property.

yea there was a bunch swapping out meters here in Iowa!
so take pix of you meter serial number and make sure it matches your utility bill!

they caught a bunch of them in the des moines area...
random traffic stop too!
you have got to love profiling!!
lol!
white van, in a residential location... out of county plates!
at least the cops were watching!!


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## Nebrasky (Dec 30, 2020)

bwswede said:


> Thanks for the replies guys.
> 
> Old man, would you mind explaining your reasoning behind your answers. To the uniformed your answers are very appropriate but I have been back feeding my panel every power outage of any length for the last 30 years and since I am extremely careful I have not had a single incident. I do not run cords into the house as open doors and/or windows creates a security issue.
> 
> ...


I think it's very different.

Your utility power supplies two hots that are each 120V to an earth-referenced ground, but 240V between them. Your panel neutral is earth referenced at the main panel.

Someone correct me if I'm wrong, but I don't think your generators really have a "neutral", rather they have two hots that are each 60V to an earth-referenced ground, but 120V between them. I think your "neutral" prongs will each have 60V on them. If that's the case, I think there would be problems when you wired each of them to the panel neutral.

At the very least, if you're gonna try this, fuse each conductor from the generators to the panel. Better to fry some fuses rather than the generators or your panel.


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## somedumbguy (Sep 17, 2020)

bwswede said:


> Thanks for the replies guys.
> 
> Old man, would you mind explaining your reasoning behind your answers. To the uniformed your answers are very appropriate but I have been back feeding my panel every power outage of any length for the last 30 years and since I am extremely careful I have not had a single incident. I do not run cords into the house as open doors and/or windows creates a security issue.
> 
> ...


Blane,

Please don't do it. You are NOT eliminating the "cross contamination" of the two sides. The two sides and two generators need neutrals and you are making them share the single house neutral; so they can "cross contaminate". I can't give an expert explanation of why your plan won't work, but I can say that the two "hot" wires coming into your house from the power company are not independent; they are a single phase and come from a single physical source which assures that the timing/alternation of the two alternating power streams can offset properly on the neutral. Just combining all the neutrals will not guarantee that precise offset will happen; two independent generators combined can produce a totally weirdo waveform and damage the generators and your appliances. 

The single/shared neutral wiring in your home works OK with utility power because the single voltage phase is locked together by the generation of the two 120 feeds. In the utility case, its more like a single 240V source is split in half with each side keeping the same timing beat to assure the coordination. 

But ... you mention that these are inverter generators. Inverter generators CAN be combined with a "parallel kit". into a SINGLE 120V source; in your case you should be able to produce a single 120V, 4400 Watt source using the two generators connected through the parallel kit. The output of the parallel kit is one hot wire, one neutral and one ground. I believe this works with inverter generators because they have enough smart electronics to coordinate the timings of the two generators via a parallel controller and make sure they are precisely aligned and do not "cross contaminate" each other. 

Here's something you might want to look into; use a parallel kit to create one voltage source, then feed the single parallel kit "hot" into both hot sides of your house in parallel. (Turn off all your 240V circuit breakers as well as disconnect from the utility grid). I have to tell you that I considered doing this personally, but wasn't TOTALLY confident it was 100% safe. 95% maybe. Even if it is more-or-less safe; I doubt that it is legal. I have no personal experience with parallel kits; it appears they are manufacturer and even model specific. Here's some info for your generator model:
Amazon.com : Honda EU2200i 2200W 120-Volt Portable Inverter Generator with Companion and Parallel Cables : Home Audio & Theater 
Looks like it is just cables; but other brands parallel kits are cables and a control box. Maybe give Honda a call and see what they advise. Wow; looking at this picture on the Amazon site I see that the two generators shown are slightly different; one is labelled EU2200i _Companion _and has different sockets. Definitely proceed with caution.

I would love to know if this approach works but I don't have the nerve to try it personally, or the wallet to get myself back online if it smokes. Please let us know what happens if you try it out


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## Nebrasky (Dec 30, 2020)

somedumbguy said:


> Inverter generators CAN be combined with a "parallel kit". into a SINGLE 120V source; in your case you should be able to produce a single 120V, 4400 Watt source using the two generators connected through the parallel kit. *The output of the parallel kit is one hot wire, one neutral and one ground. *


Is it? I'm pretty sure that the output of the individual generators is actually two hots and a ground. I have no idea if the parallel kit changes things (it might in the case of these Honda's, with the special "companion"), but I would guess that most of them do not. 

So, if he really has two 60V hots, and tries to wire one of them up to an earth referenced ground, I'm pretty sure that some of the magic smoke is going to come out somewhere.


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## tabora (Sep 6, 2018)

Nebrasky said:


> if he really has two 60V hots


No. If you parallel two 120V inverter generators, you have a single 120V hot to neutral at the sum of the generators amperages. 








If you're dealing with 240V, you have two 120V hot to neutral lines, but they are 180 degrees out of phase with each other, so the voltage between them is 240V.


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## somedumbguy (Sep 17, 2020)

Nebrasky said:


> Is it? I'm pretty sure that the output of the individual generators is actually two hots and a ground. I have no idea if the parallel kit changes things (it might in the case of these Honda's, with the special "companion"), but I would guess that most of them do not.
> 
> So, if he really has two 60V hots, and tries to wire one of them up to an earth referenced ground, I'm pretty sure that some of the magic smoke is going to come out somewhere.


Nebrasky, Are you saying that the double 60V hot system is true of generators in general, including conventional? Or just inverter types? People have been backfeeding their houses (illegally) with generators for a long time without (always) smoking their house electrical system, and backfeeding does indirectly connect the generator to an earth ground. (Its not a good idea to backfeed; they risk dangerous electrical shocks to themselves and utility workers, but it can produce electricity without smoke). So I don't think the earth referenced grounding itself is the issue here. Most generators can work in a floating or bonded neutral configuration and connect to their own ground rod. (But ground rods are only done in special circumstances; don't do it. Call an electrician). But if there really are two 60V hots as you say, something keeps them on exactly the same timing/heartbeat/phase so that the alternating 60V sources combine to 120 all the time. Just like tabora's chart that shows two 120s combining to produce 240. The 240 wouldn't work right if the two 120s were not in the same phase. I do agree with you that neutral in a generator is not quite the same as the neutral as we understand it in our house and that generation of 120V in a generator is not as simple as a Hot and Neutral wire.


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## tvl (Nov 14, 2018)

From my understanding, and I'm certainly no expert, both terminals on a floating neutral generator are hot OR read voltage as per the following link: (_OR is it simply stray coupling??_)

Differences Between Bonded and Floating Neutral Generators.

I started a thread a while back in regards to combining my neutral and ground and the thread can be found here: Floating Neutral

I'm aware my thread was a somewhat different subject, but maybe it can help. However, in my case, I ONLY run the generator in a standalone mode. But, *BEFORE* tying the neutral to ground, I did get a reading of approximately 60 volts when reading *EACH *of the receptacle's terminals to the ground of the generator.

*Please disregard this post if it is irrelevant! I'm trying to understand all of this generator stuff myself and I am following closely!*


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## Nebrasky (Dec 30, 2020)

somedumbguy said:


> Nebrasky, Are you saying that the double 60V hot system is true of generators in general, including conventional? Or just inverter types?


I'm talking only about 120V inverters, and specifically the Honda 2200i's that the OP has. I have a Predator clone of that generator, and mine is a split-phase 60V hot system. It's exactly like tabora's chart, except that instead of +120 and -120 combining to make 240, you have +60 and -60 combining to make 120. 
The two lines from a single generator must be kept in phase, as you say, so that they always combine to 120V. But, unless you have the proper paralleling connection between the two generators, there is nothing keeping the lines from two different generators in phase. The OP wants to take one line from each generator and tie them together at the panel neutral. If they are both 60V hots, as I understand it, I would think that would be a problem. 
Now, I have never tried to earth reference my invertor generator's neutral. TVL's thread is an interesting experiment. He said that both the lines on his invertor generator measured 60v to ground BEFORE he tied the "neutral" to the ground. But after bonding, the generator apparently continues to function normally. I have no idea what's going on there. I'm very curious what the other outlet voltage measures now, after he plugs in his bonding plug. Maybe the generator electronics can shift to a 120V hot/grounded neutral system. I don't know. 
I may have to make up my own bonding plug now, and try it with my generator. Except I'm going to fuse that bond. 

Even aside from all that, I don't think that what the OP wants to do is safe under any circumstances. Let's say that he's got two conventional generators, each with a 120V hot and a bonded earth-referenced neutral. Unlike the utility power, there's absolutely nothing keeping those hots in phase. So current from generator A is going to run to bus A on the panel. Whenever the OP uses an appliance on that bus, the current flows through the appliance to the neutral bus. Same thing for generator B and bus B. But the currents from the two different generators are not in phase at least half the time. If he's using 1500 watts from both generators, he could end up with 3000 watts on the panel neutral. And likely there would be wildly fluctuating voltages and amperages as the two generators move in and out of phase. I would think that would create problems that way as well. 
But I could be completely wrong about that. I do think it's worth thinking about.


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## Nebrasky (Dec 30, 2020)

tvl said:


> I'm aware my thread was a somewhat different subject, but maybe it can help. However, in my case, I ONLY run the generator in a standalone mode. But, *BEFORE* tying the neutral to ground, I did get a reading of approximately 60 volts when reading *EACH *of the receptacle's terminals to the ground of the generator.


So what do you get now for volt readings!?!


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## bwswede (Sep 13, 2020)

If there is something magical in the inverter generators that when combined together using simple cables supplied by the manufacturer synchronizes the generators phases why couldn't that conductor connection instead occur at the panel through an otherwise unused 240 breaker shorted together? If this were done wouldn't the 120 circuits (which are the only circuits being powered) on both sides of the panel's neutrals be fine tied together since they would all be in phase? Sure this would create an unbalanced load but we only talking about 30 amps max being sent back out the panel's neutral feed. I am sure that size of load occurs a lot of the time when the panel is powered by the utility grid.


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## somedumbguy (Sep 17, 2020)

bwswede said:


> If there is something magical in the inverter generators that when combined together using *simple cables* supplied by the manufacturer synchronizes the generators phases why couldn't that conductor connection instead occur at the panel through an otherwise unused 240 breaker shorted together? If this were done wouldn't the 120 circuits (which are the only circuits being powered) on both sides of the panel's neutrals be fine tied together since they would all be in phase? Sure this would create an unbalanced load but we only talking about 30 amps max being sent back out the panel's neutral feed. I am sure that size of load occurs a lot of the time when the panel is powered by the utility grid.


They are not simple cables. This picture is from the Amazon site. Note that the label on the generator says "special cables" and they plug into specific spots. I believe there is circuitry inside the generators that perform the synchronization, but only when they are plugged together in this specific way. The parallel kits themselves are not expensive, so it wouldn't be worth trying to create a workaround to obtain their functionality if that is what you are trying to accomplish. The remaining question to me is ifconnection to earth grounding causes the problem Nebrasky suspects. (Messing up the 60+60 design of the generator).


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## somedumbguy (Sep 17, 2020)

bwswede ... you say you have a pair of generators already. Do you have the "companion" pair and or a parallel kit/cable of some kind?


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## Nebrasky (Dec 30, 2020)

bwswede said:


> If there is something magical in the inverter generators that when combined together using simple cables supplied by the manufacturer synchronizes the generators phases why couldn't that conductor connection instead occur at the panel through an otherwise unused 240 breaker shorted together?


A parallel kit has additional wiring that plugs into the parallel ports on each of the generators to allow synchronization. Were you planning to wire that up as well?



bwswede said:


> If this were done wouldn't the 120 circuits (which are the only circuits being powered) on both sides of the panel's neutrals be fine tied together since they would all be in phase? Sure this would create an unbalanced load but we only talking about 30 amps max being sent back out the panel's neutral feed.


If the wiring can handle it, that's fine. 

I'm not trying to be argumentative. All that I really know is that my invertor generator, and probably yours as well, produce a split-phase 120V that has 60V on each side of the 120V wiring. When you wire that up the way I think you're suggesting, I don't think you're going to get 120V at the house sockets. Maybe you will, I haven't tried it. It just seems like you're more likely have some pretty wildly gyrating voltages anywhere from 60 to 180v, if you don't fry something first. Hence my suggestion of fusing every conductor from the generators. 

You might be fine, I don't know. I just don't see how hooking up a 60v hot to one side of your panel and an unrelated 60v hot to the other side is going to give you normal 120V on your house circuits.


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## tvl (Nov 14, 2018)

Not being as knowledgeable as almost everyone else on this forum, I'm a little hesitant to make any type comment. However, because of some research, I would like to make mention of the floating neutral generator's that are out there in the world ................ such as my *Honda EU3000is*:

1) On a floating neutral generator the following is true *AND* the following is a quote form an article I read: "_In a floating neutral generator, since the neutral is *not bonded* to the generator’s frame, both wires are normally current carrying wires. Therefore, both slots of the receptacles on the generator are considered live/*hot* receptacles." _

2) It's my understanding these type generators are shipped with floating neutrals because it appears it is expected these generators will likely be connected to a home's service panel. Once this is done, the neutral becomes bonded to the ground at that point. Why? ......... as most here already know, the neutral AND ground connections in a home's service panel are tied together OR bonded!

3) Bonding at the generator *AND* the service panel creates ground loops ................. which is another subject in itself. I guess Honda took the safest approach and shipped the units with a floating neutral because it eliminates the possibility of bonding in two different places, if the unit is truly to be connected to the home's service panel. However, although the generator can be run in standalone mode with a floating neutral, it also presents other issues .................. which again, is another subject in itself.

4) *The main thing I wanted to point out in regards to bonding a neutral to the ground lug of a generator is as follows*:

A- If a generator *with a floating neutral* is connected to a home's service panel, it is then *no different* than running the unit in a standalone mode with the neutral tied or bonded to the ground lug of the generator. (_As a side note: in this case it is also important to have the standalone generator connected to an appropriate ground rod!!_)

B- I had to draw this out in order to "see" that it's the same thing. Visualize your generator being tied to your home's service panel. Again, visualize how the neutral wires *AND* the ground wires are all tied together inside the service panel. They are truly bonded! If these two wires are tied together *OR *bonded *OR* jumpered in the service panel, then they are in essence tied together in the generator as well. In other words, when one operates a floating neutral generator as a backup unit (tied to the home's service panel), the bond occurs at the service panel box. The bond OR jumper truly exist, it is simply inside the service panel some distance away from the generator. Therefore, why can't one run a floating neutral generator in standalone mode with a bond or jumper at the unit? They can because it's the exact same either way you do it *AND* it also makes the generator a little safer this way .................... which goes back to my other thread.

My post has likely "muddied the water" from the OP's original intent, but I am trying to help address what appears to be a concern with bonding a generator. Unless I've interpreted some of the messages incorrectly, it is permissible and safe ................... at least from all of my research!


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## somedumbguy (Sep 17, 2020)

tvl said:


> Not being as knowledgeable as almost everyone else on this forum, I'm a little hesitant to make any type comment. However, because of some research, I would like to make mention of the floating neutral generator's that are out there in the world ................ such as my *Honda EU3000is*:
> 
> *1) On a floating neutral generator the following is true AND the following is a quote form an article I read: "*_*In a floating neutral generator, since the neutral is not bonded to the generator’s frame, both wires are normally current carrying wires. Therefore, both slots of the receptacles on the generator are considered live/hot receptacles." *_


tvl; you don't say where you read this, but it is easily misinterpreted as written. It suggests that if the neutral WAS bonded to the frame then the neutral would NOT be live/hot and that the neutral would NOT carry current. This is not true. The "hot" wire and the neutral wire ALWAYS carry the same current. (If they don't, something is faulty). The concept they are trying to explain here should be expressed with voltages, not current. In the floating system, both wires carry the exact same current. And in a bonded system they carry the same current as of they were floating! The difference is that a hot wire has a voltage potential different than ground and can cause the current to flow to ground. The neutral wire in a bonded system can't cause current to flow to ground. In that sense it is not "hot" but it is still not 100% "safe". It may be connected to ground but is not the same thing as ground.

About this part: "2) It's my understanding these type generators are shipped with floating neutrals because it appears it is expected these generators will likely be connected to a home's service panel. " I believe 120V inverter generators are most often used for camping and RVing. They do not have the proper outlet that would allow them to be correctlyconnected to a home service panel.


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## tvl (Nov 14, 2018)

somedumbguy said:


> I believe 120V inverter generators are most often used for camping and RVing. They do not have the proper outlet that would allow them to be correctly connected to a home service panel.


And that is a very true statement! I was simply trying not to relate to the other possibilities of where a small generator might be used. But, from my research, it does appear there are *instances* where a small floating neutral generator might be utilized where it is connected to some type service where there is a neutral and ground bond. I'm thinking Honda and other manufacturers were simply trying to make things as safe as possible; thus their reason for floating the neutral???

However, from my studies thus far and when used in a standalone mode, I still believe the neutral and ground should be bonded ....................... *AND* the generator properly connected to a ground rod.

Another reason I feel this way is because when a generator is connected to a home's service panel, the neutral *and *ground always become bonded ............... and in essence, that's all the way back to the generator itself. Therefore, it obviously doesn't hurt or affect the generator, but it must be important??? As mentioned in another post: _"The neutral is tied to ground just to give the system a ground reference. It prevents the potential of the system from rising too high above that of ground. It also allows breakers to trip in the event that an ungrounded conductor faults to ground. Without the neutral being connected to ground, an ungrounded conductor contacting ground would not trip a breaker."

Some information you were curious about was derived from the following article!: Differences Between Bonded and Floating Neutral Generators

*Anyway, I'm probably getting in over my head at this point so I will just watch for a while!*_


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## tabora (Sep 6, 2018)

Nebrasky said:


> Someone correct me if I'm wrong, but I don't think your generators really have a "neutral", rather they have two hots that are each 60V to an earth-referenced ground, but 120V between them. I think your "neutral" prongs will each have 60V on them.


Wow, just WOW!!! There is no 60V. You must be measuring it incorrectly. It's 120V hot to neutral. Neutral to Ground should be close to 0V. In fact, if the generator is bonded, they are at unity.

This is the output from my floating neutral generator, and you can see that the two hots are 118.5V 180 degrees apart and the neutral and ground are at 1.1V, referenced against utility ground.


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## bwswede (Sep 13, 2020)

> somedumbguy said:
> 
> 
> > They are not simple cables. This picture is from the Amazon site. Note that the label on the generator says "special cables" and they plug into specific spots. I believe there is circuitry inside the generators that perform the synchronization, but only when they are plugged together in this specific way.


I am betting that you are correct. And yes, I already have the cable kit.



somedumbguy said:


> bwswede ... you say you have a pair of generators already. Do you have the "companion" pair and or a parallel kit/cable of some kind?


Yes, I have a pair of generators. One of them is the standard model and the other is the companion model. My understanding is that you can hook two standard models together and get the 4400 peak watts. I believe the selling point of the companion model is the RV 30 amp plug. The paired generators will not put out 30 amps but at least the unit allow an RV to plug into the 4400 watt system.



somedumbguy said:


> bwswede ... you say you have a pair of generators already. Do you have the "companion" pair and or a parallel kit/cable of some kind?


I wasn't planning to but I believe somedumbguy is correct in that the cables need to be plugged in to synchronize the generators. Now my current thinking is to plug in the cables to sync the generators and then plug in the outdoor receptacles (one from each side of the panel) to allow my 120v outlets in the house to be energized.



Nebrasky said:


> I'm not trying to be argumentative. All that I really know is that my invertor generator, and probably yours as well, produce a split-phase 120V that has 60V on each side of the 120V wiring. When you wire that up the way I think you're suggesting, I don't think you're going to get 120V at the house sockets. Maybe you will, I haven't tried it. It just seems like you're more likely have some pretty wildly gyrating voltages anywhere from 60 to 180v, if you don't fry something first. Hence my suggestion of fusing every conductor from the generators.
> 
> You might be fine, I don't know. I just don't see how hooking up a 60v hot to one side of your panel and an unrelated 60v hot to the other side is going to give you normal 120V on your house circuits.


I am glad you are raising the point because I don't know at this time what is going to happen. Today is the first I have heard of the 60v issue. I don't see why the generators would only put out 60v in any method or setup. There is a youtube video with a guy showing how one generator like mine runs his circular saw (somewhat poorly) and then it shows him connecting two generators like mine via the cables and the circular saw running like it would off utility power. 



tvl said:


> Not being as knowledgeable as almost everyone else on this forum, I'm a little hesitant to make any type comment. However, because of some research, I would like to make mention of the floating neutral generator's that are out there in the world ................ such as my *Honda EU3000is*:


Like tvl's generator these are also floating neutral units.

Great discussion guys. This is fascinating.

Blane


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## Nebrasky (Dec 30, 2020)

tabora said:


> Wow, just WOW!!! There is no 60V. You must be measuring it incorrectly. It's 120V hot to neutral. Neutral to Ground should be close to 0V. In fact, if the generator is bonded, they are at unity.
> 
> This is the output from my floating neutral generator, and you can see that the two hots are 118.5V 180 degrees apart and the neutral and ground are at 1.1V, referenced against utility ground.
> View attachment 8606



You have a generator putting out 240 volts. That's not what I'm talking about. I'm referring only to the Honda 120v 2000 watt suitcase invertors and their clones. I'm not talking about all floating neutral generators, but only about these particular invertor generators. 

Maybe the Predator clone is different from the Honda original that the OP has, but I doubt it. This is what I'm measuring. 64.9v hot to ground, 63.6 "neutral" to ground, 123.8v hot to neutral 
Which part am I doing incorrectly?





















I

I realize that doesn't total correctly. Santa dropped off an oscilloscope for Christmas, I need to get that set up and see if the legs are off a bit or just how ugly that signal looks.


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## tabora (Sep 6, 2018)

Nebrasky said:


> This is what I'm measuring. 64.9v hot to ground, 63.6 "neutral" to ground, 123.8v hot to neutral
> Which part am I doing incorrectly?


It's certainly unusual. I'm surprised that they're allowed to have them that way. "Real" generators don't do that. Yet another reason to buy a Honda! And yet another reason not to try tying one of these generators into your house wiring or into an RV with a voltage monitoring system.

I did a search, and another person reported seeing the same behavior on a Predator 2000:
_I have two Harbor freight generators. I was checking the out put with a vom meter and here is what I found. On a house hold receptacle you have three plugs. One is ground, one is neutral and one is 110-120.(hot) In checking both generators I find that one terminal is ground and 60 volt on each of the either two terminals or 120 when checked together. Some one said that these generators are designed to only run power tools, and will even damage some of them, if they have any diodes in them. And said never plug any thing electronic into them. I have two other older generators and you get a 120 volt reading when you connect between hot and neutral or hot and ground. I am wondering if any one else has checked their China made generators. Maybe some one else more enlightened can answer this question._​​I just found another reference as well. Apparently cheap Chinese-designed inverters do work this way:
_The Honda and Yamaha generators generate a true 120v output. Pretty much ALL of the other [Chinese] generators (including mine) produce a +60/-60 volt signal. That’s +60 on the hot leg and -60 on the ground leg (not the neutral). _​​_I installed this power monitor system (Hughes Autoformers PWD50-EPO) just before adding the generator. The power monitor system worked great, until I tried to use it with the generator. The power monitor would not allow the RV to power up when connected to the generator. Turns out, this is because it’s not a true 120v. The power monitor detects the -60v on the ground line and it says there’s a problem._​


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## tabora (Sep 6, 2018)

Further info on this situation from Samlex... I'll summarize it here: If you have one of these 60/-60V inverter generators, DO NOT connect it to any fixed NEC infrastructure (described in sections 8 & 9 in Green). Only use it with items plugged directly into the on-board outlets. Pay particular attention to sections 10 & 11 in Red. There, I learned something today!

*1. What is the conductor configuration for single phase AC Power transmission?*
For single phase transmission of AC power or DC power, two conductors are required that will be carrying the current. These are called the "current-carrying" conductors. A third conductor is used for grounding to prevent the build up of voltages that may result in undue hazards to the connected equipment or persons. This is called the "non current-carrying" conductor (will carry current only under ground fault conditions).

*2. What does the term "grounded" indicate?*
The term "grounded" indicates that one or more parts of the electrical system are connected to earth, which is considered to have zero voltage or potential. In some areas, the term "earthing" is used instead of grounding.

*3. What is a "grounded conductor"?*
A "grounded conductor" is a "current-carrying" conductor that normally carries current and is also connected to earth. Examples are the "neutral" conductor in AC wiring and the negative conductor in many DC systems. A "grounded system" is a system in which one of the current-carrying conductors is grounded.

*4. What is an "equipment grounding conductor"?*
An "equipment grounding conductor" is a conductor that does not normally carry current (except under fault conditions) and is also connected to earth. It is used to connect the exposed metal surfaces of electrical equipment together and then to ground. Examples are the bare copper conductor in non-metallic sheathed cable (Romex®) and the green, insulated conductor in power cords in portable equipment. These equipment-grounding conductors help to prevent electric shock and allow over-current devices to operate properly when ground faults occur. The size of this conductor should be coordinated with the size of the over-current devices involved

*5. What is a "grounding electrode"?*
A "grounding electrode" is the metallic device that is used to make actual contact with the earth. Other types of grounding electrodes include metal water pipes and metal building frames.

*6. What is a "grounding electrode conductor"?*
A "grounding electrode conductor" is the conductor between a common single grounding point in the system and the grounding electrode

*7. What does a "Bond" refer to?*
"Bond" refers to the connection between the "grounded conductor", the "equipment grounding" conductors and the "grounding electrode" conductor. Bonding is also used to describe connecting all of the exposed metal surfaces together to complete the equipment-grounding conductors.

*8. What does a "grounded electrical power distribution system" refer to?*
The National Electrical Code (NEC) requires the use of a "grounded electrical distribution system" for a permanently connected AC power source. As per this system, one of the two current-carrying conductors is required to be grounded. This grounded conductor is called the "Neutral / Cold / Return". As this conductor is bonded to earth ground, it will be at near zero voltage or potential. There is no risk of electrical shock if this conductor is touched. The other current carrying conductor is called the "Line / Live / Hot". The connection between the "Neutral" and the grounding electrode conductor is made only at one point in the system. This is known as the system ground. This single point connection (bond) is usually made in the service entrance or in the load center. If this connection is inadvertently made in more than one place, then unwanted currents will flow in the equipment grounding conductors. These unwanted currents may cause inverters and charge controllers to be unreliable and may interfere with the operation of ground-fault detectors and over-current devices.
NOTE: In a single phase AC power source, a current-carrying conductor that is not bonded to the earth ground cannot be called a "neutral". This conductor will be at an elevated voltage with respect to the earth ground and may produce electrical shock when touched.

*9. What is the polarity and color codes for power cords, plugs and receptacles used with 120 V, 60 Hz electrical systems?*
Single phase 120 VAC, 60 Hz AC devices and appliances use 2 pole, 3 wire grounding configuration for making AC side connections. The plug / receptacle has three pins / slots - two flat pins / slots (also called poles) that are connected to the two current-carrying conductors and a round pin / slot which is connected to a non-current carrying conductor (this will carry current only during ground fault conditions). One flat pin / slot is connected to a black current-carrying conductor which is also called "Line/Live/Hot" pole. The other flat pin / slot is connected to the white current-carrying conductor also called the "Neutral / Return / Cold" pole. The third round pin / slot is connected to the non-current carrying green "equipment grounding conductor". This green "equipment grounding conductor" is bonded to the metal chassis of the device or appliance. The plug (for example 15 A, NEMA5-15P) will mate with the corresponding female slots of the NEMA 5-15R receptacle

*10. What precaution should be taken in inverters where none of the current carrying conductors is bonded to the chassis?*
In some inverters designed for portable use, the two current carrying conductors connected to the "Line/Live/Hot" slot and the "Neutral / Return / Cold" slot of the receptacle (for example, 15A NEMA5-15R) are isolated from the metal chassis of the inverter. In these inverters, none of the two poles can be called Neutral as both these poles are isolated from the chassis of the inverter. Both the Line and Neutral slots of the receptacle will be at an elevated voltage with respect to the chassis - normally around 60 VAC (Half of the voltage between the two current carrying conductors). Hence, do not touch the neutral slot of the receptacle!

These types of inverters are designed to be connected directly to the AC loads. These are not designed to be permanently installed into household or recreational vehicle AC distribution wiring. As this type of connection / installation can not be classified as a permanent installation, the NEC requirement of grounded distribution system doesn't strictly apply.

*11. What are the standards pertaining to inverters where none of the current carrying conductors is bonded to the chassis?*
The UL standard for this type of inverters - UL458 - does not have a requirement for a bonded neutral on the output of inverters. As long as the installation requirement of grounding the chassis of the inverter has been accomplished, loads that are plugged in will have their chassis held at the same ground potential as the chassis of the inverter and the house or RV. The only difference is that the neutral slot of the receptacle has approximately 60V on it instead of the usual 0V. The impact of this is minimal, since parts of wiring and equipment that are connected to the neutral side of the circuit are required by safety standards to be treated as if they were at 120VAC, since there are many receptacles that are wired backwards or 2-prong plugs that are not polarized. Therefore, a voltage of approximately 60VAC of the Neutral slot is not accessible to the user, and any shock hazard presented is mitigated by lack of access. The main safety agencies, CSA, UL, and ETL, have all approved inverters with this half-voltage on the neutral scheme.


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## tabora (Sep 6, 2018)

bwswede said:


> I am glad you are raising the point because I don't know at this time what is going to happen. Today is the first I have heard of the 60v issue. I don't see why the generators would only put out 60v in any method or setup.





Nebrasky said:


> Maybe the Predator clone is different from the Honda original that the OP has, but I doubt it.


So, to further summarize. Hondas apparently don't do this weird 60/-60V thing and therefore CAN be connected to NEC infrastructure. Predators and other cheap portable-only inverter generators should not be. Check your 120V inverters! Now you Honda/Yamaha owners know what you've paid extra for.


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## iowagold (Jan 22, 2020)

AMEN! Tab! good work!
I have been trying to tell folks this for years...
only to be silenced by mods.
the real deal units are the way to go!

there are other things in the designs that make the phantom voltage on the chassis.
Hint think capacitance and induction folks.
without spoiling the secret sauce this is as far as i will go in open forum.
the good brands protect from this issue with a proper design.


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## tvl (Nov 14, 2018)

Well, I hate to say that info is incorrect, BECAUSE my *Honda EU3000is* reads approximately 60 Volts on each leg to ground when floating. I even connected an oscilloscope to one leg and read 63.3 VAC. Here is a photo image of one of the readings:

RMS = 63.3 V which can be clearly seen at the bottom of the display
Vpp = 192 V


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## Nebrasky (Dec 30, 2020)

tabora said:


> So, to further summarize. Hondas apparently don't do this weird 60/-60V thing and therefore CAN be connected to NEC infrastructure. Predators and other cheap portable-only inverter generators should not be. Check your 120V inverters! Now you Honda/Yamaha owners know what you've paid extra for.



Well, this has been educational all around. I didn't realize that the Honda inverters were different in that regard. That, to me, would be the biggest reason to go Honda over the clones. I'm a bit surprised that this difference isn't mentioned in the advertising. 
I did find some references on line suggesting that the older Honda 2000i generators should not be connected to a building but that the newer 2200i could be. But there was no mention as to why. I wonder if that was a change with the new models. But actual documentation from the manufacturer on this topic is frustratingly difficult to find.


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## Nebrasky (Dec 30, 2020)

tvl said:


> Well, I hate to say that info is incorrect, BUT my *Honda EU3000is* reads approximately 60 Volts on each leg to ground when floating. I even connected an oscilloscope to one leg and read 63.3 VAC. Here is a photo image of one of the readings:
> 
> RMS = 63.3 V which can be clearly seen at the bottom of the display
> Vpp = 192 V
> ...


What happens when you plug in your bonding plug? What does the voltage on the other outlet read?


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## somedumbguy (Sep 17, 2020)

Nebrasky said:


> What happens when you plug in your bonding plug? What does the voltage on the other outlet read?


What's a bonding plug?


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## Nebrasky (Dec 30, 2020)

somedumbguy said:


> What's a bonding plug?


tvl had mentioned an older thread on the previous page: Floating Neutral


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## tvl (Nov 14, 2018)

I'm off to do a *LOT *more research in an attempt to fully understand what is going on *AND* what is *OR* is not safe to do. I'm speaking in regards to bonding and grounding .................. which for now, I believe is *OK in my case* ! But, maybe not yours!!!!

I just saw the following from another site and will include it for what it's worth. There's a lot more behind this one comment, thus the reason for my getting a better handle on things before I make any further replies:


*Wayne XXXXX posted*_: I just gathered some data from my EU2000i and wrote it down this time because I keep forgetting it.

With the generator off:

1. DC resistance from either AC output side to generator ground is greater than 10 megohms, in both polarity directions.
2. Capacitance from either AC output side to ground is about 25 nanofarads.

With the generator running and no loads connected:

1. Measured AC voltage from either AC output side to ground is about 62 volts.
2. Short-circuit AC current from either AC output side to ground is about 1.5 milliamps.


As a science experiment to demonstrate that the 62 volt measurements are insignificant and consistent with *stray coupling* I took a roll of about 150 feet of 12-2 w/ground romex, powered the hot and neutral with 120 volts AC, and *left the ground unconnected*. In this setup a voltmeter reads about 62 volts between the hot or neutral and ground, same as the EU2000i. The short-circuit current is 0.2 ma., and the capacitance between the hot and ground is about 5 nanofarads, roughly proportional to the EU2000i readings.

As a second experiment I tried to light an LED connected to one side of the EU2000i's AC output and the generator ground. It did not light, and the current was 0.65 ma. which with the prior data would be expected when hooking a diode between an AC output and ground.

I submit that this is more than enough data that it is safe to hook either side of the EU2000i's output to the generator ground, and it's easy enough to verify for yourself. To limit the risk while verifying, place a night light bulb (4 or 7 watt) in the circuit
when trying things, and use a meter that can handle at least a tenth of an amp. Then the biggest risk of this information being wrong is that the bulb will light up. _


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## somedumbguy (Sep 17, 2020)

This dialog has been VERY useful. bwswede, do you have the means to hook up your specific Hondas in parallel and take voltage measurements across all three pairs of outputs at the 30Amp receptacle? 

I do not recommend that you use your revised plan either; at least not without much more testing/analysis. (By_ "_revised plan" I mean _"Now my current thinking is to plug in the cables to sync the generators and then plug in the outdoor receptacles (one from each side of the panel) to allow my 120v outlets in the house to be energized."_ ) Do you mean you plugging in to your house in two places with cords that have male plugs at both ends? (aka "suicide cords") As we know, that is a code no-no. Aside from the code issue, this only has a chance of working if you make absolutely sure that the neutrals on both house outlets are fed from the same 60V "hot" from the generator. Otherwise you will be connecting the two different hots (60v hots) together via the neutral bonding inside your house. I don't know what that would do. Short out? Cancel out? Also, be aware that old houses (or even newer ones that have been incorrectly added onto) are notorious for ignoring the wiring conventions for what we now call "hot" and "neutral"; black wire, white wire etc. So you can't assume you will get polarity right from the visual appearance of the outlet slots; you'd need to do continuity testing. (An old house I had at one time had newer living space that was apparently converted from a breezeway; they tapped the circuit going to the garage for a sequence of outlets in the new space. These new outlets were chained one to another without any consistency of hot/neutral at the outlet slot locations.)

If the generators do produce two 60V hots, and if you do get the polarities right and this plan does produce 120 inside the house, there seems to be no way to avoid send 60V up the neutral to the utility feed. (Does removing the meter disconnect the neutral?). And that 60V on the neutral is also connected to ground unless you undo the bonding. (Next to impossible at my house). That bothers me. Without a path back to the other 60v source, this may not matter, but there are waaaaay too many "ifs" here for me to be comfortable! Who knows what this does to GFCI protections.


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## tvl (Nov 14, 2018)

May not be needed by most here, but the following is an excellent short video.


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## tvl (Nov 14, 2018)

I finally found information from another site that seems to validate my own personal findings. *Attached is the conversation* between two individuals and I can provide the link to the site if needed:

Orlando says:
February 4, 2014 at 11:07 pm
Hi Mike,

This is a great post with very valuable information. I need some help. I just purchased a new Honda Eu3000is (Canadian model) that has a floating neutral. I have checked the voltage output at the generator and I have found 63 volts on the (neutral) to ground and 64 volts on the (hot) to ground connection on the receptacle. Across the neutral and hot from the generator I have 127 volts.

I wanted to hook up a transfer switch in my main house panel. The 6 circuit transfer switch does not break the neutral. It only breaks the loads. I am afraid of attaching this to my main panel. I know the main panel has a Bonded neutral. The transfer switch has a ground and neutral wire that requires attachment to the main panel neutral and ground connections. I have read over the internet that connecting this generator to this configuration will blow the inverter. I tried contacting Honda and they referred me to the dealer who also did not have an answer. What is your opinion? Can this be done?

I also tried connecting the generator to my furnace that has a circuit board by using an extension cord. The furnace will not start in heating at all. Once I put generator power to the furnace plug that I attached to the furnace, I get an error code that states Reverse Polarity. I believe this is due to the furnace not liking the power on the generator neutral side. I know this is also due to a floating neutral. Can I use the NG bond plug to correct this problem? I am just worried I am going to damage the generator. If I am using the NG bond plug can I still plug other appliances into the generator at the same time?

Regards Orlando


Mike Sokol says:
February 5, 2014 at 8:58 am
You really don’t have a problem. Since your Honda EU3000is has a floating neutral, it’s just a matter of understanding when you need to add your own G-N bond. The main point to remember is that your should always have ONE and ONLY ONE point of Ground-Neutral bonding. As delivered your Honda generator has NONE, which is fine for running portable tools such as a drill.

So here’s your first scenario. If you’re connecting it to the house service panel via a transfer switch, the house service panel will provide the G-N bond along with a ground-rod connection. I call this a G-N-E bond and it’s supposed to be done on EVERY incoming service panel. Since your house panel provides the G-N bond, then you don’t need (or want) a G-N bond on your generator. So connecting the floating generator directly to your transfer switch is just fine and the neutral should now measure 0-volts to ground and 120-volts to hot.

In the second scenario of connecting it directly to your furnace with an extension cord, you have the opposite condition. Your generator doesn’t have a G-N bond and your furnace power supply doesn’t have a G-N bond either. So you need to provide ONE G-N bond which is as simple as using the G-N bonding plug illustrated in this article. Just plug the G-N bonding plug into one of your generator outlets, and plug your extension cord into the other generator outlet. You should then measure the correct 0-volts from neutral to ground and 120-volts from neutral to hot. You can also plug in any other appliances to your generator with the bonding plug in place.

As far as damage to your generator, I’ve had dozens (maybe hundreds) of readers use my little bonding plug without any problems. Modern inverter-generators are very smart, so if they don’t like a load they simply shut down without damaging themselves. And Honda tech support has told me (off the record, of course) that it should be fine. But try using the G-N bonding plug first and measure your generator outlet with both a 3-light cube tester as well as a voltmeter. I’ll bet everything will work perfectly using a G-N plug for running a single appliance such as a furnace, or not using a G-N plug for feeding the transfer switch feeding your home service panel. BTW: What brand/model transfer switch are you using and can you email me a picture of the installation?

Please report back here with what you find out.


Orlando says:
February 5, 2014 at 10:24 pm
Hi Mike,

I just wanted to say thanks for your great help on my questions. I started my Honda EU3000 today and plugged in a 3 light circuit tester. The circuit tester showed an open ground. I made a GN Bond plug and plugged it into one of my receptacles on the generator. I then reconnected the 3 light tester and it now shows “correct”. I used a multi-meter and found 127 volts between neutral and the hot leg. From neutral to ground I have 0 volts and hot to ground is 127 volts. This is the same power arrangement as my house. I plugged in an extension cord and wired it into my furnace with the hot, neutral and ground wiring. I also plugged in my hot water tank which is gas fired but uses an Hot surface ignitor to ignite the fuel and they both worked flawlessly. This is without grounding my generator grounding stud. I now have heat when the power goes out.

Can I make the GN Bond at the end of my extension cord instead of back at the generator? The end of the extension cord consists of a 2 X 4 metal box with a receptacle plug. I would be making the GN Bond right at the receptacle screw terminals and then plugging right into the metal box receptacle. I would think this would be the same as making it back at the generator, but I would have to use this extension cord for the generator only and not for other uses.

Can I use a jumper wire to the generator ground stud to one of my metal electrical boxes as a ground or should I install a grounding rod? Do I really need to ground the generator stud?

My transfer switch is an older Generac Model 1276. I have not installed it yet but I will definitely send you some pictures of the install once the weather gets warmer.

Thanks again


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## somedumbguy (Sep 17, 2020)

tvl said:


> I'm off to do a *LOT *more research in an attempt to fully understand what is going on *AND* what is *OR* is not safe to do. I'm speaking in regards to bonding and grounding .................. which for now, I believe is *OK in my case* ! But, maybe not yours!!!!
> 
> I just saw the following from another site and will include it for what it's worth. There's a lot more behind this one comment, thus the reason for my getting a better handle on things before I make any further replies:
> 
> ...


TVL, I missed your latest comment before I sent my last post. I am not sure that I completely understand the science experiment results; if that interpretation is correct (that the 60V thing is basically a red herring) would you expect that either "hot" leg could be connected to the house neutral, or is one leg special?. When the neutral, whatever leg it is, is connected inside the house to ground it will be bonded to the "real" ground ground, not the generator frame/ground. Does that make a difference? That isn't part of the experiment. I would LOVE to believe this 2-generator house feed approach works, but I'll wait until bwswede does a live test on his house to validate the coils of wire and LED simulations  
You mention "short circuit current" twice. What was shorted to what? Could the generator itself have detected the short and limited the current? Sorry to be a Doubting Thomas but a lot is at stake. (I have been fooled by my owned enthusiasm more than once into doing things that weren't quite right)!


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## motormonkey (Jul 10, 2016)

That 60 volts on both line and neutral could just be due to voltage being coupled through some fairly low value line filter capacitors between line/ground and neutral/ground in the generator's output. That's commonly done.

Apply some kind of load, such as a hundred watt incandescent light bulb, between neutral and ground, and I'll bet that neutral/ground voltage will drop to zero or very near zero. If it does, you're okay to ground the neutral.


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## tvl (Nov 14, 2018)

motormonkey said:


> That 60 volts on both line and neutral could just be due to voltage being coupled through some fairly low value line filter capacitors between line/ground and neutral/ground in the generator's output. That's commonly done.
> 
> Apply some kind of load, such as a hundred watt incandescent light bulb, between neutral and ground, and I'll bet that neutral/ground voltage will drop to zero or very near zero. If it does, you're okay to ground the neutral.


That's what I was alluding to earlier: _*stray coupling*_ - however, that was based on another individuals findings and I was simply "riding on their coattail".


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## Nebrasky (Dec 30, 2020)

motormonkey said:


> That 60 volts on both line and neutral could just be due to voltage being coupled through some fairly low value line filter capacitors between line/ground and neutral/ground in the generator's output. That's commonly done.
> 
> Apply some kind of load, such as a hundred watt incandescent light bulb, between neutral and ground, and I'll bet that neutral/ground voltage will drop to zero or very near zero. If it does, you're okay to ground the neutral.


Perhaps that would be the case on the Honda's, I can't speak for them. It's not the case on my Predator 2000. I played around with the oscilloscope this evening. I may not have all the settings figured out correctly just yet. 
But WOW, is this predator BAD!!!
These probes are wired up so that the green/yellow channel is connected to the nominal "hot" prong of the 120v plug and the purple channel is connected to the nominal "neutral" prong. A three-way splitter pigtail is plugged into the generator, then a heater is plugged into one of those outlets and the probes are plugged into another of them. 
First picture is no load, the heater is turned off. 









Second picture, the 600 watt element on the heater is turned on:









Third, both the 600 watt and the 900 watt elements are both on:









We were playing around with it, and this picture is with the pigtail plugged into the utility mains and a small squirrelcage fan is running. So, in this case, the green line is the utility power, and the purple line is the return voltage on the bonded neutral. They aren't magnified the same in this image, but you can compare the utility main to the predator signal. 








These pictures were taken while we were figuring out the oscilloscope and just playing around with it. Tomorrow I need to do a more serious study with it, and make sure all the settings are consistent.


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## iowagold (Jan 22, 2020)

GRIN!


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## tvl (Nov 14, 2018)

Readings at the bottom of your scope indicate a voltage of ~ 5.60V
You're looking for a much greater voltage than that .................... correct?

As motor monkey has stated; it is likely just coupling OR phantom voltage!

*IF* I'm interpreting your scope correctly, the scope is setup for 10 Volts per division meaning the sine wave is only approximately 20 Vpp??????


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## somedumbguy (Sep 17, 2020)

I don't have an RV, but I think that the 30 Amp plug on bwswede's Companion generator is designed to connect to a standard 120V RV electrical system inlet box in a simple/standard way. If we understood the manufacturer's intentions when designing generators to support RVs out of the box, we might get some clues on how to use such a generator on a house. Does an RV have a neutral convention? I'm assuming that it has a ground that is bonded to the metal shell of the RV. Is that bonded to the neutral? I don't think an RV uses a ground rod, so I wouldn't expect the RV to have an analog of the house neutral to earth ground bonding. 

I am very curious to know what the 120V (only) inverter generator manuals say about "neutral". I don't have any generators like this. Do they ever use that term? I'm looking at the pictures of bwswede's pair of hondas; the Companion says "Neutral floating" near the 30A outlet but I can't tell which slot, if either, is considered neutral. The 20A outlet looks like it has a slot that is hot and a slot that is neutral, but its not clear from the picture how/if they align with the two "hot" slots on the 30A outlet. Does the polarity implied by the slots on the standard 20A outlet really mean anything or is that just that just to accommodate a variety of plug types. (Do the two 20A outlets even have the same polarity?)

Do the manuals (or online resources) for these types of gens describe a process for bonding the neutral of the generator? How about an attachment point for a ground rod? Or even warnings that bonding and ground rods should not be attempted? 

Sorry to pose all these questions, bwswede. I do think its possible to accomplish what you are trying to do, but risky. I went through a similar thought process several months ago but got cold feet and bought an open frame 120/240 inverter gen for my house that didn't pose these challenges in the hook-up. I don't use anything 240 in my house except the AC, and I don't think my gen is really big enough to support AC without turning off some other important stuff. It was disappointing to sacrifice the additional quietness and flexibility of the smaller generators to get the hookup I do need along with the 240 I don't need, but I don't worry about getting smoked!


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## motormonkey (Jul 10, 2016)

Nebrasky said:


> Perhaps that would be the case on the Honda's, I can't speak for them. It's not the case on my Predator 2000. I played around with the oscilloscope this evening. I may not have all the settings figured out correctly just yet.
> But WOW, is this predator BAD!!!
> These probes are wired up so that the green/yellow channel is connected to the nominal "hot" prong of the 120v plug and the purple channel is connected to the nominal "neutral" prong. A three-way splitter pigtail is plugged into the generator, then a heater is plugged into one of those outlets and the probes are plugged into another of them.
> First picture is no load, the heater is turned off.
> ...


You are measuring voltages between line and neutral, with the expected normal results. (noisy as they may be) That does not indicate anything about the voltages between line/ground and/or neutral/ground, which are what is in question here.

Voltage between neutral and ground may well be 60 volts because there is no current flow between these conductors the way you have it wired. To see if the line/neutral circuit is actually floating, you would need to *apply some minimal load between neutral and ground*, and then measure the voltage across those conductors.


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## Nebrasky (Dec 30, 2020)

motormonkey said:


> You are measuring voltages between line and neutral, with the expected normal results. (noisy as they may be) That does not indicate anything about the voltages between line/ground and/or neutral/ground, which are what is in question here.
> 
> Voltage between neutral and ground may well be 60 volts because there is no current flow between these conductors the way you have it wired. To see if the line/neutral circuit is actually floating, you would need to *apply some minimal load between neutral and ground*, and then measure the voltage across those conductors.


One channel is measuring line to ground and other channel is measuring neutral to ground. Two separate grounded probes, two separate channels. The grounds for both probes are hooked up the generator ground. I didn't expect back feeding there to cause much problem. It didn't actually change the picture much when I unhooked the grounds. 
I do not have probes hooked up line to neutral. I had 600 watts load between line and neutral in the second picture, 1500 watts in the third picture. 

You want me to connect a 60watt incandescent bulb between neutral and ground? Hook it up so that the "line" , normally black wire, of the light fixture connects to the "neutral" conductor coming from the generator? And the neutral, normally white wire, of the fixture connects back to the rounded ground prong of the generator? 

I can do that, just wanted to make sure I understand what you mean. If I do that, what voltage readings are you interested in seeing? I'd probably just use the multimeter in that case.


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## Nebrasky (Dec 30, 2020)

tvl said:


> Readings at the bottom of your scope indicate a voltage of ~ 5.60V
> You're looking for a much greater voltage than that .................... correct?
> 
> As motor monkey has stated; it is likely just coupling OR phantom voltage!
> ...


There's a 10X reduction on those numbers, and some of the other setting aren't ideal either. Don't pay too much attention to them at the moment. I'll try to straighten it out this afternoon. Maybe the picture will change.


Earlier, before getting out the oscilloscope, I had plugged the heater directly into the generator and watched voltages with the multimeter. At 600 watts of load, the multimeter still showed approximately 60 volts between either flat prong and the ground. At 1500 watts of load, the multimeter showed voltages spiking as high as 90/30 before drifting back down to 60/60. 
So, I do need to play around with this some more and make sure I'm reading things correctly.


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## tvl (Nov 14, 2018)

Nebrasky said:


> You want me to connect a 60watt incandescent bulb between neutral and ground? Hook it up so that the "line" , normally black wire, of the light fixture connects to the "neutral" conductor coming from the generator? And the neutral, normally white wire, of the fixture connects back to the rounded ground prong of the generator?


That is exactly what he is implying. Once the bulb is connected in this manner, if we are truly "seeing" phantom voltage - which I do believe is the case, then the voltage reading will drop from ~ 60 VAC to approximately 0 VAC.

Therefore, your reading of ~ 60 VAC will be seen *BEFORE* connecting the bulb and then a reading of approximately 0 VAC will be seen *AFTER* loading the circuit with the bulb. Again, the bulb is put in the circuit between the neutral slot of the receptacle and the ground slot. You can also do this between the hot and ground as well and report your voltage readings. I do believe you will find both scenarios go to 0 volts.

Again, I'm assuming you're experimenting with a floating neutral generator as is the case with mine.


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## tvl (Nov 14, 2018)

Nebrasky said:


> There's a 10X reduction on those numbers, and some of the other setting aren't ideal either. Don't pay too much attention to them at the moment. I'll try to straighten it out this afternoon. Maybe the picture will change.


Oh!!!! You probably didn't have the correct probe setting selected in the scopes software!!!!!


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## Nebrasky (Dec 30, 2020)

tvl said:


> Oh!!!! You probably didn't have the correct probe setting selected in the scopes software!!!!!


No, the probe settings and the scope settings didn't match. Which may have been much of the problem. The manual for the scope is not that helpful, I'm rewatching a few youtubes to get all the settings sorted out.


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## tvl (Nov 14, 2018)

Nebrasky said:


> I'm rewatching a few youtubes to get all the settings sorted out.


I'm not sure how familiar you are with scopes, but the following video is a must see if you're new to this type equipment. Otherwise, please just disregard it.


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## motormonkey (Jul 10, 2016)

Nebrasky said:


> ...
> 
> You want me to connect a 60watt incandescent bulb between neutral and ground? Hook it up so that the "line" , normally black wire, of the light fixture connects to the "neutral" conductor coming from the generator? And the neutral, normally white wire, of the fixture connects back to the rounded ground prong of the generator?
> 
> I can do that, just wanted to make sure I understand what you mean. If I do that, what voltage readings are you interested in seeing? I'd probably just use the multimeter in that case.


Yes, that is exactly what you need to do, and yes, measure the voltage across the light bulb, from ground to neutral.


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## Nebrasky (Dec 30, 2020)

tvl said:


> I'm not sure how familiar you are with scopes, but the following video is a must see if you're new to this type equipment. Otherwise, please just disregard it.


Yeah, I hadn't watched that one, but I did watch ElectroBOOM's video on scopes. He covered that part pretty well.


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## Nebrasky (Dec 30, 2020)

motormonkey said:


> Yes, that is exactly what you need to do, and yes, measure the voltage across the light bulb, from ground to neutral.


Hopefully this adventure will be helpful to others as well. It's educational for me, for sure.

I got the bulb hooked up and it doesn't light up. There's some voltage reading across it, the volt meter jiggles around a bit but stays under 5. So it's not enough to light anything up.
With the bulb plugged in, line to ground reads 124 or so.
Without the bulb plugged, the ESP surge protector won't transmit current. With the bulb plugged in, it does. Presumably, the voltage on the neutral triggers something in the ESP and shuts it down. 
So bonding the neutral does indeed straighten out the signal generation. The oscilloscope shows a much better looking signal than before. And it's filterable. Running it through the ESP gives a perfect looking signal that's actually better than the utility mains.

Editing to add pictures: 
For reference, this is a sample of the unbonded voltage output with no load.









Ugly nastiness. Nothing lines up. In the picture above, the scope settings are correct so it gives the correct voltages.
It doesn't get much better when you plug in a normal tool or load. At least they're more synchronized, but it still can't be good for tools or electronics:









But go ahead and bond earth-neutral, and voila! 









Still a little fuzzy at the peaks, but not bad. 
Let's zoom in on a peak. 









What do you guys think? Good enough? I noticed the scope wasn't sure how to count the hertz, ended up counting all the little harmonics(?) to come up with 129Hz. But we're zoomed in pretty far here. 
However, I have ESP power conditioners. Here's what comes through when you plug that into the bonded generator. 









That's perfect, even if we did lose a couple volts. 
Pretty smooth now:









Compared to utility power: 



















So it's probably very possible to set up two generators as the OP originally suggested, as long as the wiring and grounding can handle the completely unbalanced load. 

My last question would be in the construction of a grounding plug. Is it better to wire up a dead short between the neutral and ground to bond the generator, or better to wire in a resistor in place of the incandescent bulb?


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## iowagold (Jan 22, 2020)

if you are doing a generator as a stand alone power for an rv you are supposed to have a green ground stake at the generator. this makes the chassis as referenced to the ground at the generator location.

on a house setup with a floating chassis generator, the green ground is connected to the main panel that has all of the green ground as proper.
one ground for the whole house thing.
they bond the neutral to green ground in the main box to nec code.


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## iowagold (Jan 22, 2020)

Nebrasky said:


> My last question would be in the construction of a grounding plug. Is it better to wire up a dead short between the neutral and ground to bond the generator, or better to wire in a resistor in place of the incandescent bulb?


is this for rv use or for home back up power or for a construction site?


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## Nebrasky (Dec 30, 2020)

iowagold said:


> is this for rv use or for home back up power or for a construction site?


The primary use is going to be at work sites. I can't imagine that ugly non-bonded signal is going to be good for battery chargers or any other tools. That would be where I'd need the bonding plug. It might be ok for engine block heaters to be plugged into that nastiness, but I'd rather not even do that. 

The freezer and fridge in my house are on the same circuit, and I had hoped to set up a switch to use this generator to power just that circuit. The neutral and ground would both flow back to the main panel in that case. That bond would give the same function as the bulb that I had wired up, correct?


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## somedumbguy (Sep 17, 2020)

iowagold said:


> _*if you are doing a generator as a stand alone power for an rv you are supposed to have a green ground stake at the generator. *_this makes the chassis as referenced to the ground at the generator location.
> 
> on a house setup with a floating chassis generator, the green ground is connected to the main panel that has all of the green ground as proper.
> one ground for the whole house thing.
> they bond the neutral to green ground in the main box to nec code.


iowagold; I've been trying to understand RV elec systems and ran across this article; 
RV Electricity – Generator grounding and bonding - RV Travel 
That guy says "_ You *DO NOT* need to use an earth “grounding rod” for any portable generator that’s powering a single RV. However, if you’re using a large generator to distribute power to a number of RVs for a rally, that’s an entirely different thing which will require a grounding rod. _" 
This seems like a pretty knowledgeable guy. But he also says "The simplest way to Ground/Neutral bond a generator is to use the G/N plug I invented. Just plug it into any 15- or 20-amp outlet on the generator panel and *it will bond the entire generator’s electrical system*. Here’s a *link* to where you can purchase one. " I don't know exactly what he means by "bond the entire generator's electrical system". But taken literally, I'm pretty sure that's a bad idea! 
I always try to keep in mind that intentional grounding is done to make the most likely shock hazard for the application less likely to happen, but it doesn't eliminate all hazards and can even create shock hazards that would not otherwise exist.


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## tvl (Nov 14, 2018)

Nebrasky said:


> My last question would be in the construction of a grounding plug. Is it better to wire up a dead short between the neutral and ground to bond the generator, or better to wire in a resistor in place of the incandescent bulb?


Excellent work! Your findings do match what I've seen as well. I think bonding is the right thing to do *when a gen set is used in a standalone mode* AND I feel a ground rod is also *necessary* along with the bonding ................. which is what I do!!!!!! If I encounter a ground fault, I certainly want a good ground!

In response to your last question: From my research, and I've done a LOT, I saw where one individual utilized a 100K ohm resistor with a 1/4 watt rating placed across the neutral and ground in place of a solid piece of wire. It worked fine like this, but I'm sticking with the solid piece of wire myself and here's why:

1) I don't want to lose that neutral/ground bond once it's made. I wouldn't trust a resistor in this situation .................... solid wire is much better!

2) From my research, I have discovered there are at least two reasons why some manufacturers don't bond the neutral and ground. One big reason seems to be that theses generators (yes our smaller ones are included) are sometimes connected to a home, RV, boat, etc, service panel. Our home's service panel, an RV parks power pedestal, a shore pedestal, etc. have the neutral and ground bond already in place. In these cases, the user doesn't want to connect a generator that already has a neutral/ground bond as it would go against code. Therefore, a huge reason for our floating neutral gen set .................. and a floating neutral gen set does offer some other safety advantages, but also some disadvantages when one digs deeper!

3) I'm no expert at all, but the link I've included at the end and its' *MANY* comments will shed a lot of light on this subject.

4) Some folks indicate it's dangerous or could harm the inverter generator by bonding. However, if a manufacturer provides a gen set that *CAN* be connected to a service panel or power pedestal that is already bonded, then it must be safe and harmless. Because, as I mentioned in an earlier post: _"If these two wires are tied together *OR *bonded *OR* jumpered in the service panel, then they are in essence tied together in the generator as well ............ that's if the generator is indeed connected to that panel"_

This thread has helped me learn so much more! And by the way, from my research, it does appear there are many who run their gen sets in parallel and also successfully feed a service panel. That was if the two sets were made to run in parallel and some special OR *cautious* wiring conditions must be adhered to when connecting a 120 volt ONLY gen set to a service panel.

http://noshockzone.org/generator-ground-neutral-bonding/


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## motormonkey (Jul 10, 2016)

Nebrasky said:


> Hopefully this adventure will be helpful to others as well. It's educational for me, for sure.
> 
> I got the bulb hooked up and it doesn't light up. There's some voltage reading across it, the volt meter jiggles around a bit but stays under 5. So it's not enough to light anything up.
> With the bulb plugged in, line to ground reads 124 or so.
> ...


One last thing you might want to do with that o'scope just for grins. Look at the ac waveform when measuring between line and neutral. I suspect that it will be cleaner than between line and ground.

RE your last question: The reason I initially suggested testing with the light bulb was to limit the current from neutral to ground in case the Predator's output wasn't floating. It's clear now that it is. Neutral/ground bonding is supposed to be low impedance (low resistance) so a dead short is the norm.

BTW, if you tie the generator into the house wiring as the OP intends to do, the neutral ground bonding will occur within the house wiring, and no additional bonding will be necessary.


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## bwswede (Sep 13, 2020)

somedumbguy said:


> This dialog has been VERY useful. bwswede, do you have the means to hook up your specific Hondas in parallel and take voltage measurements across all three pairs of outputs at the 30Amp receptacle?


I agree, the information provided in this post has been extremely useful. I have to admit though that I need to go back and study many of the posts as they are currently beyond my understanding of generators and electricity. Yes, I do have a way to make the measurements you describe but my generators are at my cabin which I won't be going to for several weeks.



somedumbguy said:


> I am very curious to know what the 120V (only) inverter generator manuals say about "neutral". I don't have any generators like this. Do they ever use that term? I'm looking at the pictures of bwswede's pair of hondas; the Companion says "Neutral floating" near the 30A outlet but I can't tell which slot, if either, is considered neutral. The 20A outlet looks like it has a slot that is hot and a slot that is neutral, but its not clear from the picture how/if they align with the two "hot" slots on the 30A outlet. Does the polarity implied by the slots on the standard 20A outlet really mean anything or is that just that just to accommodate a variety of plug types. (Do the two 20A outlets even have the same polarity?)


The owner's manual states the generator "has a system ground that connects generator frame components to ground terminals in the AC output receptacles. The system ground is not connected to the AC neutral wire." 

A 30 amp RV outlet is 120 v. The two opposing angled slots are hot and neutral. The separate one is the ground.



somedumbguy said:


> Sorry to pose all these questions, bwswede. I do think its possible to accomplish what you are trying to do, but risky. I went through a similar thought process several months ago but got cold feet and bought an open frame 120/240 inverter gen for my house that didn't pose these challenges in the hook-up. I don't use anything 240 in my house except the AC, and I don't think my gen is really big enough to support AC without turning off some other important stuff. It was disappointing to sacrifice the additional quietness and flexibility of the smaller generators to get the hookup I do need along with the 240 I don't need, but I don't worry about getting smoked!


I am trying to do what you first wanted to do. I haven't got cold feet yet but they aren't exactly warm either. I need to do a lot more reading of the posts in this thread and from other Internet sources. 

My understanding is that when the cables are plugged in and the generators are linked together they act as a single generator that happens to be powered by two engines. If I am correct then plugging this floating neutral generator into the house on both sides of the panel should be safe to do since everything is in the same phase. I am trying to think how is this different than what I have been doing forever with my old Coleman open frame generator plugged into one side of the panel. In that case all the 1/2 the neutrals are tied together and 1/2 the panel was powered up. In my proposed situation I want to add the other 1/2 of the panel which would simply add more neutrals to the already tied together neutrals. If I am missing some important point I hope someone will let me know.

Thank you for all for the very helpful discussion. I need to dig deeper into some of the posts. Especially ones speaking about 60v. Those comments have me confused.

Blane


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## tvl (Nov 14, 2018)

.


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## somedumbguy (Sep 17, 2020)

[QUOTE="bwswede, post: 77482, member: 379.
I am trying to think how is this different than what I have been doing forever with my old Coleman open frame generator plugged into one side of the panel. In that case all the 1/2 the neutrals are tied together and 1/2 the panel was powered up. In my proposed situation I want to add the other 1/2 of the panel which would simply add more neutrals to the already tied together neutrals. If I am missing some important point I hope someone will let me know.

Blane
[/QUOTE]
Blane. The good news is I think the real tech guys on this thread are now thinking that the measurement of two hot 60V legs is just a ghost phenomenon and can be ignored. (Guys; correct me if I didn't sum that up correctly.) The generator really does have one 120 hot and one neutral. And it sounds like your manual confirms you have a neutral and a hot, and tells you which one is which on the 30A outlet. So no need to be concerned about sending rogue voltages up the utility neutral wire. You could approach this like you did on your "half" solution with your coleman, except for a couple things.

1. First, when you connected your coleman to 1/2 the circuits via one of the two hot sides of the panel, you actually could have gone ahead and connected BOTH hot sides of the panel to the one hot wire from the generator, and lit up the whole panel with 120. That is what you would basically need to do with the new generators, except that ...

2. ... you will not treat the two sides like they are separate halves. Even though you have two generators, you can't make them supply two halves independently. You should think of it as super-sizing one generator; and using that one source to light both sides of the panel through the companion parallel stuff you got with the pair of generators.

3. I am willing to bet that your panel neutrals are NOT set up 1/2 and 1/2 like the hot wires are. The neutrals are all the same. When you connected your coleman neutral I believe to really connected it to all the neutrals, not just half. 

4. If you don't have any 240V circuits, this method doesn't restrict you at all. But if you do have 240V circuits they must be turned off. At best, they won't work and at worst its a short circuit fire hazard. I am not savvy enough to know exactly what will happen but I think the main risk you have is firing up the generator and forgetting to turn off any 240 circuits then melting you new generators or burning the place down. I hope some other folks can comment on this.

5. It would be great if you can get an interlock for your panel to prevent the possibility of cross connecting generator and utility power. There is no way to make this code legal without $$$ and electricians. But at least you need to be aware of the possible risks, how to reduce them, and hope you caught them all. I know some, but not all.


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## pharbrian (Nov 16, 2020)

I have a 3000 watt 120 volt Honda EU3000ISAG powering both legs of my electrical panel.
I use an L5-30P Male to L14-30R female adapter connected to the generator that has an integrated jumper connecting the two hot leads (X & Y prongs) on the output side of the adapter. This feeds both legs of my electrical panel with 120 volts. I am connecting through an interlock kit. I make sure that I turn off my 240 volt breakers and keep them off with this setup. I can run my while house with this setup minus my AC and range. (I have a gas dryer.) I have to limit high power devices, such as my microwave, to one at a time to avoid overdrawing my generator.
Here is the link for the adapter I am using: https://www.amazon.com/dp/B01MDJYFDI/ref=cm_sw_r_cp_apa_fabc_S3W9FbAJHQ24T?_encoding=UTF8&psc=1


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## somedumbguy (Sep 17, 2020)

pharbrian said:


> I have a 3000 watt 120 volt Honda EU3000ISAG powering both legs of my electrical panel.
> I use an L5-30P Male to L14-30R female adapter connected to the generator that has an integrated jumper connecting the two hot leads (X & Y prongs) on the output side of the adapter. This feeds both legs of my electrical panel with 120 volts. I am connecting through an interlock kit. I make sure that I turn off my 240 volt breakers and keep them off with this setup. I can run my while house with this setup minus my AC and range. (I have a gas dryer.) I have to limit high power devices, such as my microwave, to one at a time to avoid overdrawing my generator.
> Here is the link for the adapter I am using: https://www.amazon.com/dp/B01MDJYFDI/ref=cm_sw_r_cp_apa_fabc_S3W9FbAJHQ24T?_encoding=UTF8&psc=1


Yes, that plug looks like what you need if you are using a standard L14-30 120/240v 30 Amp inlet box on the house. That plug is better than a homemade jumper; if I was going to use 120 on both hots of the house, that's how I would do it. I'm not optimistic that this would pass muster with a building inspector, though. (And that plug doesn't show any UL type markings). On my panel, it is possible to buy little "locks" to prevent individual breakers from being turned on or off. I would consider getting them for the 240V breakers even though you are aware that they must be off. Accidents happen. (I turn all the breakers off individually and flip them back one by one after the generator has been powered up and connected to the panel. I could see myself losing track of where the 240 breakers are while doing this in partial darkness in the basement, then flipping one on by mistake).


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## pharbrian (Nov 16, 2020)

somedumbguy said:


> Yes, that plug looks like what you need if you are using a standard L14-30 120/240v 30 Amp inlet box on the house. That plug is better than a homemade jumper; if I was going to use 120 on both hots of the house, that's how I would do it. I'm not optimistic that this would pass muster with a building inspector, though. (And that plug doesn't show any UL type markings). On my panel, it is possible to buy little "locks" to prevent individual breakers from being turned on or off. I would consider getting them for the 240V breakers even though you are aware that they must be off. Accidents happen. (I turn all the breakers off individually and flip them back one by one after the generator has been powered up and connected to the panel. I could see myself losing track of where the 240 breakers are while doing this in partial darkness in the basement, then flipping one on by mistake).


I received the blessing of the electrician I hired to install my generator inlet and reviewed with him how I would be using my generator with the adapter mentioned in my above post. Moreover, if I were to have any kind of home inspection in the future, the generator would not be hooked up at that time of the inspection. 
The lockouts are not a bad idea for preventing accidental use of the 240 volt circuits. My wife and I are comfortable with bright sticker labels we placed on those circuits as a reminder to keep them de-energized when running off generator power. I think you could run into human error with the lockouts as well by forgetting to place them on the 240 volt circuits when using the generator. We also have a laminated checklist we run through to help prevent human error. 
We also turn off all circuits and activate them one at a time when first running on generator power to avoid inrush current overdrawing the generator.


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## iowagold (Jan 22, 2020)

you can always do the lock out tag out kit for breakers.


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## somedumbguy (Sep 17, 2020)

pharbrian said:


> _ We also have a laminated checklist we run through to help prevent human error._


I'm impressed! Sure beats my handwritten notes on the back on an envelope tucked between cables coming out the top of the panel.

Here's the lockouts I use; its a lockon in my case so I don't accidentally turn off the dedicated circuit for the wired-in smoke detectors. 
Square D by Schneider Electric HLO1CP Circuit Breaker Handle Lock Off Kit - - Amazon.com 

BTW. I really don't know if its necessary to lock out the 240V circuits. If they are not locked out you would just be applying the same 120 voltage potential to both sides of the load which wouldn't cause any current to flow; or so I think. But why take a chance.


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## tabora (Sep 6, 2018)

pharbrian said:


> I think you could run into human error with the lockouts as well by forgetting to place them on the 240 volt circuits


Depending on the number of 240V breakers, you could place them all together at the top on the left or right side of the breaker panel, below the interlocked inlet breaker. That way they're all easy to isolate/remember.


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## tabora (Sep 6, 2018)

somedumbguy said:


> BTW. I really don't know if its necessary to lock out the 240V circuits. If they are not locked out you would just be applying the same 120 voltage potential to both sides of the load which wouldn't cause any current to flow; or so I think. But why take a chance.


They would both be in phase, though, not out of phase by 180 degrees like they're supposed to be. The items in a 240V appliance that only use 120V from one leg would likely be OK (for example the circuit boards and light bulbs in a range), but if someone tried to energize a 240V widget like a burner, the outcome MIGHT depend on how the device is wired internally. I would like to think that the bridged 120V legs would do nothing, but some things might try to come on with 120V to neutral/ground?


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## iowagold (Jan 22, 2020)

or you could do a sub panel for the 240 or the 120 vac stuff....
then do the inter lock on that panel.

most folks do a gen items sub panel with an interlock.

most electric stoves have split voltage on the burners..
for low settings they use 120 vac....
at least on the ones I have.
not all brands are wired the same.


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## somedumbguy (Sep 17, 2020)

iowagold said:


> or you could do a sub panel for the 240 or the 120 vac stuff....
> then do the inter lock on that panel.
> 
> most folks do a gen items sub panel with an interlock.
> ...


Wow. How do those split voltage stoves get wired at the panel? Are there two breakers?


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## Old man here (Nov 5, 2020)

somedumbguy said:


> Wow. How do those split voltage stoves get wired at the panel? Are there two breakers?


The stove is wired to 240V using two hot wires (one hot from one 120V side of the electrical panel and the other hot from the other 120V side of the electrical panel). There is also a Ground wire and a Neutral wire connected to the stove.
Any 120V function of the stove will only be powered thru one hot wire, the Ground, and Common wires.
This provides the 120V. The other hot wire is not in that 120V circuit.


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## somedumbguy (Sep 17, 2020)

OK. Thanks. Do those two circuits need to be right next to each other in the panel and locked together for code safety reasons so they both trip if one trips? Can it also just single breaker used for simple 240v loads like this? 
Square D QO 40-Amp 2-Pole Standard Trip Circuit Breaker in the Circuit Breakers department at Lowes.com 
I never thought about it before, but little things like a little 120V oven light in an electric oven would be supplied by a big amperage breaker. Seems weird.


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## Old man here (Nov 5, 2020)

No, they are the double breaker style with the tie bar.
This is the breaker in the panel for my range, no 120V breaker is used.


https://www.lowes.com/pd/Square-D-Homeline-30-Amp-2-Pole-Standard-Trip-Circuit-Breaker/1014737


Edit, the breaker you linked to is a 240V breaker. It is used in some certain panels. Not my Reliance panel though. I suppose they both serve the same purpose, supply 240V.


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## Old man here (Nov 5, 2020)

Also, a short to ground in the 120V wiring of the stove would still trip the 240V breaker.


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## iowagold (Jan 22, 2020)

yea they run as 120 / 120 and 240 inside the stove assy's.
at least on some brands.
so for the low burner setting it can be 120 vac.
now on new glass top units and induction units most are computer controlled heat.
and are 240.
look up the wiring diagram for your exact make and model of stove.
or look on the rear of the stove or under the top.
they used to place the wiring diagram there.


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## somedumbguy (Sep 17, 2020)

Thanks guys for explaining this 120/240 circuit stuff. I don't have any three wire 240V loads like a stove in my panel; only a two wire 240V air cond. compressor circuit with a breaker like the one I linked. I didn't understand how a 240 breaker works; I was thinking it was basically one fuse limiting the combined current running through both hots but it seems like it is two fuses measuring each hot side independently but tripping together. Even though my AC compressor breaker has what looks like a single handle, I think it may still be a double internally like the one in Old Man's link. Maybe I will try to figure this out with a meter. (I was surprised that I couldn't easily find a simplified diagram of how a circuit breaker works)!


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## tvl (Nov 14, 2018)

somedumbguy said:


> (I was surprised that I couldn't easily find a simplified diagram of how a circuit breaker works)!


Check out the following video. It may OR may not be what you're looking for!


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## tabora (Sep 6, 2018)

tvl said:


> Check out the following video. It may OR may not be what you're looking for!


Excellent video - that's a keeper!


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## somedumbguy (Sep 17, 2020)

tvl said:


> Check out the following video. It may OR may not be what you're looking for!


Yes, that's a very cool video. (I especially liked the current dots running back and forth to indicate AC flow). One thing I didn't like too much was descriptions of the neutral wire. They say the neutral wire works in a 120v circuit as "returning the used current to the transformer." That's a useful simplified explanation but they don't show any "used current" returning to the transformer for a 240V circuit. That is correct for pure 240V loads because all current is on the hots. But in a circuit with a mixed 120/240 load protected by a 2pole breaker, like the stove iowagold described (or a breaker that feeds a subpanel), some of that "used current" will go back on the neutral. ("Used current" makes it sound like neutral current has lost its oomph or is not as dangerous as "hot" current; that's not a good way to think of it. ). The visuals did help me understand why I was confused about breakers for 240 circuits; I thought there were two different kinds; one for mixed 120/240V circuits and another for pure 240. I did a simple test a of a spare 240 2 pole breaker. It appears to function exactly as two single pole breakers glued together measuring the current on the two hots independently with two different breakers. That works for mixed 120/240 or pure 240 circuits. Here's what I didn't originally understand:
1. I thought that a pure 240V load would use a breaker that would somehow measure the combined current in a 240v load at only one point and also somehow prevent mismatched current on the two hot legs. Now I don't think that is possible, at least not without using more complicated breakers with circuitry like the ones at the end of the video used to detect ground faults and arc faults)
2. Someone else here explained that normal breakers are only required to prevent the house wiring itself from overheating from excessive current. But when an appliance is connected to the house wiring , then the appliance itself has to protect its own wiring with its own fuses if it can't handle the full rated current of the circuit. 
3. Even though neutral wires only carry "used" current (whatever that is) care must be taken not to cause excessive current on the neutral. Neutral wires are not fused, but they can still carry all of the same current as the hot wires and can overheat just as easily. This is only safe in a 120V circuit when the current in a specific neutral wire is always "returning" the current from only one hot circuit that has its hot wire fused at the same capacity as the neutral wire.
4. The neutral wire in a 120/240V circuit _can _share one neutral wire for its two hots because of a special property of the 120/240 voltage being fed to your home from the utility. As explained in the video, the two hots are 180 degrees out of phase. Here's an example: a 30 amp 240/120V circuit wired with a 3 wire 10 gauge copper cable. At an instant in time; if one hot wire is drawing 25 amps and the other is drawing 20, then the total current on the neutral wire they share is 25-20 = 5. Not 25+20= 45. The 180 degree offset allows this to work OK. The two separately fused hot wires can share a neutral and never risk exceeding its capacity even though the neutral wire is not fused. The maximum current on the neutral, 30 amps, can only occur when only one hot is actually drawing power at 30 amps. The physical attachment of two 120 breakers to make a single 240 breaker is essential to making this safe. It assures that both hots are turned off even if the excess current only appears on one hot leg. It is not _electrically _necessary for the two 120V breakers to be right next to each other or physically attached; they could be anywhere in the box on two different bussbars, but that would potentially dangerous for a variety for reasons. The interleaving of the two hot bussbars in the panel as shown in the video assures that two breakers installed next to each other are on two different bussbars. 

Sorry for the long description; it may sound like a nitpick of a good video. But, in my opinion, wiring safety issues are usually a result of neutral and ground mistakes due to misunderstanding of their function. Everyone is careful with hot wires because they know hot wires are, um, hot! 

The video doesn't say much about ground as it relates to the utility power, either. And misunderstanding of ground can lead to safety problems too. For example, I don't think people would understand from this video that a broken/disconnected neutral wire from the utility pole to your house doesn't necessarily disrupt the 120v circuits in your house, or the 240. It may not be noticeable at all. Your house would still get source power from the hot wires; if the "used electricity can't return to the transformer through your white wire, it can usually just go into the ground from your house ground (since neutral and ground are bonded) go next door through the dirt and get back to the transformer through your neighbor's bonded ground and neutral wires! And no breakers will trip. Nobody ever knows until a neutral or ground somewhere gets hot and starts to smoke!


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## Nebrasky (Dec 30, 2020)

somedumbguy said:


> The video doesn't say much about ground as it relates to the utility power, either. And misunderstanding of ground can lead to safety problems too. For example, I don't think people would understand from this video that a broken/disconnected neutral wire from the utility pole to your house doesn't necessarily disrupt the 120v circuits in your house, or the 240. It may not be noticeable at all. Your house would still get source power from the hot wires; if the "used electricity can't return to the transformer through your white wire, it can usually just go into the ground from your house ground (since neutral and ground are bonded) go next door through the dirt and get back to the transformer through your neighbor's bonded ground and neutral wires! And no breakers will trip. Nobody ever knows until a neutral or ground somewhere gets hot and starts to smoke!


This brings to mind an incident that occurred at my brother's house. The boom from some machinery contacted the overhead distribution power lines, which resulted in the bottom "neutral" burning through and the two ends falling to the ground. The top "hot" wire was still intact. 
The lights in the house blinked out momentarily, and then came back on normally. My sister-in-law didn't know that anything was the matter until the utility crew knocked on the door to let her know that they were there to fix the wires. It would appear that the "used" current was flowing from one end of the broken wire over to the other end just fine. It would have been interesting to see if the voltage was any different while the wire was broken, but no one checked that.


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## iowagold (Jan 22, 2020)

that makes for a good argument for meters on the breaker panel for line.
pm me if you want to see what i did on my system.


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## somedumbguy (Sep 17, 2020)

Nebrasky said:


> This brings to mind an incident that occurred at my brother's house. The boom from some machinery contacted the overhead distribution power lines, which resulted in the bottom "neutral" burning through and the two ends falling to the ground. The top "hot" wire was still intact.
> The lights in the house blinked out momentarily, and then came back on normally. My sister-in-law didn't know that anything was the matter until the utility crew knocked on the door to let her know that they were there to fix the wires. It would appear that the "used" current was flowing from one end of the broken wire over to the other end just fine. It would have been interesting to see if the voltage was any different while the wire was broken, but no one checked that.


That's a great story Nebrasky. I wonder what would have happened if someone picked up that neutral thinking it was safe. I have to admit that I was under the impression that "white wires are safe" until I found out different the hard way; I disconnected one in a box that was in my way. A disconnected neutral wire is no longer neutral!


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## Nebrasky (Dec 30, 2020)

somedumbguy said:


> That's a great story Nebrasky. I wonder what would have happened if someone picked up that neutral thinking it was safe. I have to admit that I was under the impression that "white wires are safe" until I found out different the hard way; I disconnected one in a box that was in my way. A disconnected neutral wire is no longer neutral!


I would assume that the full current being used by my brother's house was flowing back through the soil between the two sections of wire. So if you picked one end up off the ground, then you become the next easiest path back. 

However, I don't know exactly how much return current there would be. Is there return current back from the transformer when it's feeding a balanced 240v load? Or is it just the unbalanced load flowing back on the main line? I don't know much about what's going on on the other side of the transformer. 

If it's only the unbalanced load flowing back, then we're only talking 10-15 amps of 120v. Boost that back up to whatever the distribution lines run at, and we're talking around a pretty small current. Might not be enough to kill someone, depending on the path it took through the body.

I don't know. But I've no intention of finding out either.


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## somedumbguy (Sep 17, 2020)

Nebrasky said:


> I don't know. But I've no intention of finding out either.


Me either! I have reached, or gone beyond, my level of understanding on this. (But the little voice in my head is still saying "You're not going to let a broken wire sit there like that, are you? Just wear rubber gloves, stand on dry wood, and wrap some tape around the ends; and you'll be fine." I have learned to resist these thoughts, but its still a struggle!


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## tabora (Sep 6, 2018)

Nebrasky said:


> I would assume that the full current being used by my brother's house was flowing back through the soil between the two sections of wire. So if you picked one end up off the ground, then you become the next easiest path back.





somedumbguy said:


> Me either! I have reached, or gone beyond, my level of understanding on this. (But the little voice in my head is still saying "You're not going to let a broken wire sit there like that, are you? Just wear rubber gloves, stand on dry wood, and wrap some tape around the ends; and you'll be fine." I have learned to resist these thoughts, but its still a struggle!


Central Maine Power Public Service Announcement: No line is safe to touch, evah!

__ https://twitter.com/i/web/status/688005709611593728


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## somedumbguy (Sep 17, 2020)

tabora said:


> Central Maine Power Public Service Announcement: No line is safe to touch, evah!
> 
> __ https://twitter.com/i/web/status/688005709611593728


ayuh!


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