# How to disconnect neutral from the frame of Firman T07571 Tri-fuel purchased at Costco



## GenHappy (Aug 4, 2021)

I recently purchased a Firman T07571 Tri-fuel 7500/9400 watt generator from Costco.

I also installed a Square D by Schneider Electric QO1DM10030TRBR 30-Amp Generator Main Breaker Outdoor Manual Transfer Switch.

I intend to use the generator strictly as a back-up power supply for my home and will not use it like a construction site generator.

The Square D generator transfer switch panel uses the main service panel neutral.

The owner's manual for the Firman generator states that the neutral is bonded to the frame.

I understand that the neutral cannot be grounded in two places and that I need to disconnect the neutral from the generator's frame.

My question is: What is the procedure for disconnecting the neutral from the frame for this Firman generator?

I contacted Firman with this question, but they have not yet responded.

Thanks for all replies.


----------



## Marlin (May 25, 2015)

Over the last several years, I have seen many questions about doing this, and it is inevitable a while later many of these same folks are asking if there is a quick way to reconnect the bonding for another application.

I was faced with this same problem a few years ago when I purchased my Yamaha YG2800i inverter generator.

There were instances where I wanted it to be a floating neutral, and times I wanted it to be a bonded neutral.

What to do? Well, the quickest and easiest way for me was to make up a short extension cord, one that was only about a foot long, but it was only a two conductor cord.

There was not a wire connected to the ground lug of the male plug.

Simply, plug your long extension cord into the short extension cord, plug the short extension cord into the generator and you are in business.

In effect, this does the same thing as disconnecting the bond in the generator but the plus is you are not modifying the generator and not voiding it's warranty.

If I needed the generator to be in the bonded neutral configuration, I just did not use the new short extension cord.


----------



## GenHappy (Aug 4, 2021)

Thanks for your info.

I think your suggested procedure is more for using a power cord plugged in to the generator for like running a saw. My application is attaching the generator through a transfer switch to certain house circuits. Here is the transfer switch. Square D by Schneider Electric QO1DM10030TRBR 30-Amp Generator Main Breaker Outdoor Manual Transfer Switch with 30-Amp Twist-lock Receptacle - Electrical Equipment - Amazon.com

If I can figure out how to disconnect the neutral from the frame, I would never reattach it. The only use I have for a generator is back-up power for my home.

I have searched for days exactly how to do this. I wish Firman would have the procedure on their website or FAQ's like Champion does.


----------



## Marlin (May 25, 2015)

Ok, I need to revise my reply above, I mistakenly took for granted that your Firman generator was 120 volts only.

Foolish mistake on my part.

But, my reply is still valid, only needs a slight modification. You could make up a short, one foot extension cord, with three conductors, L1, L2 and neutral, but, do not connect a wire to the ground lug.

This will accomplish the same thing.

No, I was not referencing using the generator to run a saw, for that you would need a bonded neutral and for that application you would not use the new short extension cord that you just made up.


----------



## exmar (Jun 29, 2015)

Most generators I've seen have the neutral and ground jumpered in the generator head so the two wire extension still allows the generator frame to tie to neutral which is a good thing for safety. I'd feel better if the ground were in place. 

IMHO, if ground and neutral are tied that's OK, if it's not that's also OK. Much confusion about two grounds, generators, ad nauseum. In point of fact you only have one ground at your service entrance feeding the load center (breaker box) probably a driven ground rod. You "theoretically or potentially" could get into trouble if you drove a second ground rod and terminated it at the generator-now you would have TWO grounds. Admittedly, I'm glossing over some things, but for temporary use in an outage you'll be fine.

If you're determined to disconnect the ground and neutral, get the wiring diagram for your generator and it will show where the connection is. It will probably require opening the generator head and removing a wire, if you're not comfortable doing that you'll have to get someone to do it.

If you haven't already installed the Square D unit, consider a generator disconnect, much cheaper to install. Here's a link to what they are.


----------



## GenHappy (Aug 4, 2021)

@exmar Thanks, I finished installing the switch yesterday. I can probably figure it out from the wiring diagram in the manual, I was hoping someone had already done it.


----------



## tabora (Sep 6, 2018)

GenHappy said:


> My question is: What is the procedure for disconnecting the neutral from the frame for this Firman generator?


Look in your Owner's Manual at the wiring diagram (page 37, I believe). Near the AVR there is a jumper that's tying the Neutral to the Ground. Remove it and you've floated the neutral. I've circled the jumper in red below.








It probably looks something like this:


----------



## GenHappy (Aug 4, 2021)

@tabora Ah, yes. Thank you sir! That is much appreciated! I found the diagram in my owner's manual on page 37, so I should be good to go for disconnecting the neutral. Your photos are also very helpful.


----------



## iowagold (Jan 22, 2020)

well done tab!


----------



## DL41 (9 mo ago)

GenHappy said:


> @tabora Ah, yes. Thank you sir! That is much appreciated! I found the diagram in my owner's manual on page 37, so I should be good to go for disconnecting the neutral. Your photos are also very helpful.


@GenHappy Thanks in advance for all the info! Did it work for you to disconnect the neutral from the ground? When I tried, the “Bridge Rectifier” started to overhead and smoke??


----------



## dakotamar (7 mo ago)

DL41 said:


> @GenHappy Thanks in advance for all the info! Did it work for you to disconnect the neutral from the ground? When I tried, the “Bridge Rectifier” started to overhead and smoke??


I too am looking into this, did you solve your rectifier issue? anyone able to do it? I am looking at a generlink and waiting for them to get back to me on why my generator is not listed T08072 and i suspect it is because it is bonded...


----------



## DL41 (9 mo ago)

dakotamar said:


> I too am looking into this, did you solve your rectifier issue? anyone able to do it? I am looking at a generlink and waiting for them to get back to me on why my generator is not listed T08072 and i suspect it is because it is bonded...


I contacted Firman and spoke to a very knowledgeable technician there. They sent me a new rectifier, but told me there is NO way to remove the bond on my generator (T07571). They said it will burn out every time.


----------



## tabora (Sep 6, 2018)

DL41 said:


> @GenHappy Thanks in advance for all the info! Did it work for you to disconnect the neutral from the ground? When I tried, the “Bridge Rectifier” started to overhead and smoke??


The Bridge Rectifier (blue box) should have nothing to do with the neutral bond... It's just used to convert the battery charging current.


----------



## dakotamar (7 mo ago)

tabora said:


> The Bridge Rectifier (blue box) should have nothing to do with the neutral bond... It's just used to convert the battery charging current.
> View attachment 12025


it certainly looks that way, wonder why DL41 had a problem with his..


----------



## DL41 (9 mo ago)

dakotamar said:


> it certainly looks that way, wonder why DL41 had a problem with his..


I’m definitely not an electrician, but I thought the same thing. So, I added the neutral ground bond wire back in, and the rectifier didn’t heat up and smoke. I removed the bond again, and it smoked and melted the rectifier. When I called Firman, both the tech and the parts guy said that is exactly what will happen because the wiring is more complex in that machine. What that all means, I don’t know. But I did test it, and re-test and have Firman confirm. If anybody has any additional insight, or can see something I screwed up on, I’d be happy for the feedback.

Attached is a picture of the jumper wire I removed and a picture of the rectifier before it melted


----------



## GenKnot (Dec 20, 2021)

GenHappy said:


> Attached is a picture of the jumper wire I removed


That is the correct jumper to remove to break the N-G bond.

I don't see any way for the rectifier to get fried by disconnecting the N-G bond, but apparently you have shown that to be the situation. Maybe there is something they are not showing on the schematic.

What if you disconnect the plug from the "intelligent" rectifier? Will the gen still operate normally? If it does, then I think another battery charger could be used to charge the battery.


----------



## tabora (Sep 6, 2018)

GenKnot said:


> I don't see any way for the rectifier to get fried by disconnecting the N-G bond, but apparently you have shown that to be the situation. Maybe there is something they are not showing on the schematic.


It would be interesting to see where the G/Y ground wire goes to from the 4-pin connector at the Bridge Rectifier. If it connects to a neutral rather than ground, that might do it...


GenKnot said:


> What if you disconnect the plug from the "intelligent" rectifier? Will the gen still operate normally? If it does, then I think another battery charger could be used to charge the battery.


I agree, although it looks like that 12V supply is used for the fuel cut solenoids, too...


----------



## dakotamar (7 mo ago)

schematic for the T08072 pretty much the same.


----------



## GenKnot (Dec 20, 2021)

tabora said:


> I agree, although it looks like that 12V supply is used for the fuel cut solenoids, too...


Yeah, that would be a problem.


----------



## GenKnot (Dec 20, 2021)

@tabora Well, I think I have changed my mind about disconnecting the rectifier. I think the gen should still start and run with it disconnected because the battery would supply the power to fuel solenoid and other electronics. Right?


----------



## anderep (9 mo ago)

So on systems where neutral is not disconnected from grid, interconnect switch, you are suppose to not have the ground bonded to the neutral at the generator.
Why do I care? If my neutral and ground wire are same gauge, length, and terminations. I just don’t see it as a problem.


----------



## GenKnot (Dec 20, 2021)

anderep said:


> So on systems where neutral is not disconnected from grid, interconnect switch, you are suppose to not have the ground bonded to the neutral at the generator.


Correct. That is known as *Not a Separately Derived System*. It looks something like this. Notice that the N-G bond at the generator is not there. The N-G system bond is at the far left.










anderep said:


> Why do I care? If my neutral and ground wire are same gauge, length, and terminations. I just don’t see it as a problem.


The codes state that only one N-G bond be made in an electrical system. Its all about safety. The codes have been developed over many decades and, unfortunately, revisions made after someone has died or been severely injured due to the way a system was wired. Running the system with the N-G bond in two places puts the wires in parallel. The neutral and the ground will share the current flow. This is known as objectionable current.

We can't tell you what to do...we can only point to the proper way by code.


----------



## tabora (Sep 6, 2018)

GenKnot said:


> @tabora Well, I think I have changed my mind about disconnecting the rectifier. I think the gen should still start and run with it disconnected because the battery would supply the power to fuel solenoid and other electronics. Right?


Maybe? Easy to try it if you have the generator as @DL41 does. I'd need to spend some time deciphering the function of the Dual Fuel module SM1-SM4 switches as shown in the diagram's switching chart.


----------



## anderep (9 mo ago)

anderep said:


> ...
> Why do I care? If my neutral and ground wire are same gauge, length, and terminations. I just don’t see it as a problem.


you are allowed to have parallel conductors in certain circumstances (greater then 1/0 wire), with same gage, length and terminations... i just can't get excited about it, and I'm an engineer...

there are some failure modes where it would be better and some where not...


----------



## GenKnot (Dec 20, 2021)

anderep said:


> you are allowed to have parallel conductors in certain circumstances (greater then 1/0 wire)


Yup, but it doesn't allow for neutrals and ground conductors to be paralleled to each other. You still need a minimum of 4 wires for a 120/240V system. The ECG falls under a slightly different rule [250.122(F)(1)] when it comes to paralleling.


https://www.mikeholt.com/instructor2/img/product/pdf/1220452732sample.pdf



And that would be a really big generator to require 1/0 wire in parallel! I would hate having to load that up if someone wanted to borrow it.


----------



## macdenewf (Sep 3, 2021)

GenKnot said:


> Correct. That is known as *Not a Separately Derived System*. It looks something like this. Notice that the N-G bond at the generator is not there. The N-G system bond is at the far left.
> View attachment 12041
> 
> 
> ...


I’ve watched every video i could find on this topic and still can’t sort this in my mind.

I have ( like many many others ) a portable generator that has a bonded neutral. I run a 4 conductor cable (H,H,N,G ) to a gen inlet box that is connected to a 50 Amp breaker in my panel H,H ) with the neutral and grounds tied to the panel. I manage the power between mains and generator with a mechanical interlock. 
There are no sub panels in the house so my main panel ( service panel ) has the ground and neutral bonded. I get the point where a sub panel needs to be unbonded else ground fault or imbalanced currents will travel back from the sub panel to the service panel on both neutral and ground and create all kinds of potential voltages at any point on the various loads on the sub panel and the main panel. 
Q1. Is this the same risk when running a generator? Any loads in my service panel that may become ground fault or imbalance drill have the bonded NG at the panel to clear the fault OR is the concern that there could be potential created between the panel and the gen set? 
Q2. Does code differentiate between fixed power supplies ( hard wired generator or service wires compared to a portable power ). 

Another thing I’m struggling to understand is the difference between a manual transfer switch that can unbond the neutral from the generator vs a GFI transfer switch which apparently is bein GB used by people with a gen set that has GFCI protection on all of the plugs. My gen is not GFCI protected so when I use my generator I don’t trip any breakers. 
So I guess my question is. If there is a manual transfer switch that can unbond the neutral from the generator ….is that the same as simply NOT connecting the neutral wire from my generator to my panel? 
Appreciate any thoughts 
Cheers. 
Mac.


----------



## macdenewf (Sep 3, 2021)

macdenewf said:


> I’ve watched every video i could find on this topic and still can’t sort this in my mind.
> 
> I have ( like many many others ) a portable generator that has a bonded neutral. I run a 4 conductor cable (H,H,N,G ) to a gen inlet box that is connected to a 50 Amp breaker in my panel H,H ) with the neutral and grounds tied to the panel. I manage the power between mains and generator with a mechanical interlock.
> There are no sub panels in the house so my main panel ( service panel ) has the ground and neutral bonded. I get the point where a sub panel needs to be unbonded else ground fault or imbalanced currents will travel back from the sub panel to the service panel on both neutral and ground and create all kinds of potential voltages at any point on the various loads on the sub panel and the main panel.
> ...


Forgot to add. 
or does a switched neutral transfer switch use a relay to bind the neutral when on mains then open the relay when on gen power? And is it the same as a GFI transfer switch? 
thanks.


----------



## GenKnot (Dec 20, 2021)

macdenewf said:


> I run a 4 conductor cable (H,H,N,G ) to a gen inlet box that is connected to a 50 Amp breaker in my panel H,H ) with the neutral and grounds tied to the panel. I manage the power between mains and generator with a mechanical interlock.


That is a *Not Separately Derived System* because you are not switching the neutral. You need to break the N-G bond at the gen though to get it right. Otherwise, you are putting the neutral in parallel with the EGC and causing current flow on both wires.



macdenewf said:


> Q1. Is this the same risk when running a generator? Any loads in my service panel that may become ground fault or imbalance drill have the bonded NG at the panel to clear the fault OR is the concern that there could be potential created between the panel and the gen set?


A subpanel is similar to wiring up a gen in that you do not have a N-G bond (and they often require a ground rod at the subpanel). You shouldn't have a potential between the panel and gen as long as the EGC is in place and not switched.



macdenewf said:


> Q2. Does code differentiate between fixed power supplies ( hard wired generator or service wires compared to a portable power ).


A hard wired gen is similar to a portable gen as far as wiring goes...just a few less plugs and whatnot in place with hard wiring.



macdenewf said:


> If there is a manual transfer switch that can unbond the neutral from the generator ….is that the same as simply NOT connecting the neutral wire from my generator to my panel?


You can have a *Seperately Derived System *that switches the neutral along with the two hots...if that is what you are asking. In a Separately Derived System the N-G bond at the gen stays in place and the gen has a ground rod. Also, the EGC is not switched along with the H-H-N.

^^^ At least that is the way I understand it!


----------



## GenKnot (Dec 20, 2021)

macdenewf said:


> Forgot to add.
> or does a switched neutral transfer switch use a relay to bind the neutral when on mains then open the relay when on gen power? And is it the same as a GFI transfer switch?


For those that don't (or can't) break the N-G bond at the gen, the *Seperately Derived System* is the best way to go, IMHO. A three-pole switch is needed because the neutral is switched. Those are used as GFCI transfer switches also. See this as an example...








A Manual Transfer Switch for GFCI and Bonded Neutral Generators


WINCO generators are designed with a bonded neutral, to provide worthwhile safety protections. We offer compatible manual transfer switches.




www.wincogen.com


----------



## macdenewf (Sep 3, 2021)

GenKnot said:


> For those that don't (or can't) break the N-G bond at the gen, the *Seperately Derived System* is the best way to go, IMHO. A three-pole switch is needed because the neutral is switched. Those are used as GFCI transfer switches also. See this as an example...
> 
> 
> 
> ...


I don’t think this is code but interesting analysis.


----------



## GenKnot (Dec 20, 2021)

macdenewf said:


> I don’t think this is code


Yup, not to code and should immediately fail inspection by AHJ.


----------



## GenKnot (Dec 20, 2021)

And another thought about that...

His insurance company may deny his claim should he have a fire even if it had nothing to do with the gen-house wiring. They always look for a way out of paying a claim.


----------



## macdenewf (Sep 3, 2021)

GenKnot said:


> And another thought about that...
> 
> His insurance company may deny his claim should he have a fire even if it had nothing to do with the gen-house wiring. They always look for a way out of paying a claim.


I have 2 generators. 
13000 kw propane / natural gas Mecc Alte alternator. I’ve sent Mecc Alte an email to see if they can provide the details for removing the GN bond. 

I also have a pulsar 12kw tri fuel ( converted ) generator. Similarly - I’ve reached out to them to see if they can provide details if removing the GN bond. 
Given the option I’m going to see if I can get a floating neutral that will sort all of this bonded neutral in my panel.
Will update if I hear back from either of them.
Regards

mac.


----------



## macdenewf (Sep 3, 2021)

macdenewf said:


> I have 2 generators.
> 13000 kw propane / natural gas Mecc Alte alternator. I’ve sent Mecc Alte an email to see if they can provide the details for removing the GN bond.
> 
> I also have a pulsar 12kw tri fuel ( converted ) generator. Similarly - I’ve reached out to them to see if they can provide details if removing the GN bond.
> ...


Northstar couldn’t provide


macdenewf said:


> I have 2 generators.
> 13000 kw propane / natural gas Mecc Alte alternator. I’ve sent Mecc Alte an email to see if they can provide the details for removing the GN bond.
> 
> I also have a pulsar 12kw tri fuel ( converted ) generator. Similarly - I’ve reached out to them to see if they can provide details if removing the GN bond.
> ...


so. Northstar couldn’t provide any information on de bonding GN. Pulsar replied back with pics and confirmed no issues with removing the bond.


----------



## GenKnot (Dec 20, 2021)

The Pulsar looks like a typical bonding wire. Check for continuity between ground and neutral before and after disconnecting the bond wire. Gen should not be running of course.

Look on the Northstar for a similar type bonding wire. Sometimes they are on the panel if not on the alternator.


----------



## GenKnot (Dec 20, 2021)

On the Northstar, look here...








Again, check before and after for continuity between neutral and ground at the front panel plugs.


----------



## bvedpat (7 mo ago)

DL41 said:


> I’m definitely not an electrician, but I thought the same thing. So, I added the neutral ground bond wire back in, and the rectifier didn’t heat up and smoke. I removed the bond again, and it smoked and melted the rectifier. When I called Firman, both the tech and the parts guy said that is exactly what will happen because the wiring is more complex in that machine. What that all means, I don’t know. But I did test it, and re-test and have Firman confirm. If anybody has any additional insight, or can see something I screwed up on, I’d be happy for the feedback.
> 
> Attached is a picture of the jumper wire I removed and a picture of the rectifier before it melted


@DL41- Did you find a way to converting T07571 to floating neutral? Have explored further?

Thank you in Advance!


----------



## macdenewf (Sep 3, 2021)

GenKnot said:


> On the Northstar, look here...
> View attachment 12083
> 
> Again, check before and after for continuity between neutral and ground at the front panel plugs.


My Northstar is a little different. It has a Mecc Alte 14kva alternator.
I have a pic attached below.
There are 4 posts on the terminal block.
The 2 right posts connect the hots from the alternator through to the panel.

The two posts on the right are connected to 2 different neutrals from the alternator. Odd I know but there are 2 neutral wires running from the terminal block back to the alternator. Both of these terminals are tied together with a bonding strap. Each post is also bonded back to ground with 2 bond straps. Then there is 1 neutral running to the panel.

Prior to removing GN bonds I did verify that there was continuity between G and N on my 30 amp plug.
After removing both GN bond wires I confirmed that there was NOT continuity between G and N.


Neither Mecc Alte nor Northstar would provide info on removing the GN bond. Mecc Alte said to refer to the final generator builder ( Northstar ) and NorthStar said they couldn’t comment due to it being a liability for them to instruct anyone on modifying equipment.

So. General questions

I connect to my service panel with a 4 wire gen cable. It has an 8 gauge ground ( 6 gauge hot and neutral ). My service panel does have a GN bond.

Technically speaking. Even if I remove the GN bond at the generator the system still has a GN bond through the cable and service panel….Yes? I’m trying to think about any potential issues this might create. Service or safety wise.

i rarely if ever use this generator unless it’s plugged into the house. I’m assuming the house ground at the service panel should be sufficient for a system ground vs grounding at the gen itself. Appreciate some thoughts.

lastly. I appreciate that if ever running stand alone I won’t have a GN bond and from what I’ve read this is a safety risk. Makes sense to make a 120v 3 prong male plug and jump the ground to neutral and just plug it in one of the 120 outlets. Yes?
Appreciate any thoughts.
Regards















Mac.


----------



## GenKnot (Dec 20, 2021)

macdenewf said:


> Even if I remove the GN bond at the generator the system still has a GN bond through the cable and service panel….Yes?


Yes, the distribution panel will supply the single N-G bond for the entire system (house + gen).


macdenewf said:


> I’m trying to think about any potential issues this might create. Service or safety wise.


It doesn't necessarily cause a safety issue. My new WEN GN625i came from the factory with a floating neutral. Whereas my old Champion came bonded. There isn't a standard. However, if a gen is modified from what is stated on the front panel, then a label is highly recommended so that another person using the gen down the road knows about the mod. If using the gen as a standalone unit, a N-G bonding plug can be used to quickly add the bond back to the unit.


macdenewf said:


> Both of these terminals are tied together with a bonding strap. Each post is also bonded back to ground with 2 bond straps. Then there is 1 neutral running to the panel.


So, if I am understanding that correctly, you removed the 2 wires going to ground? The bonding straps are still in place between the 2 neutral posts with 1 neutral wire going to the panel.


----------



## macdenewf (Sep 3, 2021)

GenKnot said:


> Yes, the distribution panel will supply the single N-G bond for the entire system (house + gen).
> 
> It doesn't necessarily cause a safety issue. My new WEB GN625i came from the factory with a floating neutral. Whereas my old Champion came bonded. There isn't a standard. However, if a gen is modified from what is stated on the front panel, then a label is highly recommended so that another person using the gen down the road knows about the mod. If using the gen as a standalone unit, a N-G bonding plug can be used to quickly add the bond back to the unit.
> 
> So, if I am understanding that correctly, you removed the 2 wires going to ground? The bonding straps are still in place between the 2 neutral posts with 1 neutral wire going to the panel.


I was thinking of a label as well.

Correct - Removed grounds. Left the strap between neutrals. 

Hopefully good to go now.
Thanks.


----------



## bvedpat (7 mo ago)

Anyone please advise on Firman T07571. I have heard Bridge Rectifier issues but wanted to see if anyone has successfully converted Firman to floating neutral.


----------



## MetaCipher (6 mo ago)

I’m interested in this topic as well. I have a Firman h07553, and I confirmed it’s bonded at the engine by using a voltage meter (tested with the neutral attached and detached with generator off). My only concern is the issue mentioned regarding the bridge rectifier melting. Does anyone have more information on this?

I did reach out to support at Firman and they stated the mod isn’t supported based on warranty, NOT on the technical side. I also examined the schematic and it’s very similar as ones posted in this thread.

I also want to state, for clarity and not as a recommendation (or in regard to safety), that my setup with a ProTrans 2 into my main panel does work even though the generator has a bonded neutral, AND the main panel is bonded. There’s no issues with breakers flipping (this was a short test and only mentioned for completeness - do not take this as a recommendation for setup with considering local code).

I’d like to also state there is a lot of conflicting information online from Reliance, DYIers, electricians and everything in-between. Ranging from:

Bonded vs. floating is only an issue with GFCIs tripping.
Bonded vs. floating is a code and safety issue (being shocked or worst).
Bonded vs. floating is a non-issue because power is off at utility and it will prefer the path of least resistance.
A lot of this, I’m sure, is related to local code differences, interpretation differences, and just plain “it works for me, so it must be fine”.

I should also mention, with bias, that Reliance seemingly downplays any safety concerns and only mentions tripping breakers being a concern. Their “go to” solution is to simply disconnect the neutral at the generator and be done with it.


----------



## macdenewf (Sep 3, 2021)

Not sure if anyone has asked firman but worth the email. 
I have 2 generators. A Northstar 13k and a pulsar 12k. Northstar wouldn’t provide any info on the alternator performance with the GN bond removed where as Pulsar quickly answered my email
And provided pics on which wire to remove. Worth seeing if you can find their contact info. 
cheers.


----------



## macdenewf (Sep 3, 2021)

MetaCipher said:


> I’m interested in this topic as well. I have a Firman h07553, and I confirmed it’s bonded at the engine by using a voltage meter (tested with the neutral attached and detached with generator off). My only concern is the issue mentioned regarding the bridge rectifier melting. Does anyone have more information on this?
> 
> I did reach out to support at Firman and they stated the mod isn’t supported based on warranty, NOT on the technical side. I also examined the schematic and it’s very similar as ones posted in this thread.
> 
> ...


I have a background in electrical engineering and I even find it daunting to get to a real practical answer. 

Neither of my generators have a GFCI on the generator itself and I’ve never had a problem with Tripping GFCIs in the house so I was ignorantly bliss to the issue until I read the concern on a post here

Yes. Having only one GN bond in the system is code. But that code was changed so at some point it was acceptable to have more than one. From what I can see is at some point there must have been enough instances of people getting harmed that they changed the code. And for my money….I want to be code compliant so I’ve been searching for the right solution. 

There are really 4 types of info im seeing from manufacturers. 
1. Champion as an example. They post pics of how to float the neutral on specific generators they s
2 Others like pulsar will answer the question when asked and provide instructions 
3 others refer you to a licensed electrician but I’m not certain how an electrician would
Answer a question like will removing the GN bond cause any alternator damage. 
4 Others like Northstar who simply say they can not provide any detail. 

I think I’m going to remove the bond on the Northstar and just run it in anger. Ultimately I’m more concerned about safety than damaging the unit and with no intel from the manufacturer it’s going to have to be a trial. And seeing as the bond is still in the system ( at the panel ) I’m thinking it’s a reasonable safe bet it works just fine. But will be making a jumper so if even run stand alone I can plug the jumper into an outlet on the generator and provide the GN bond through the panel. 
Cheers 
Mac


----------



## GenKnot (Dec 20, 2021)

MetaCipher said:


> My only concern is the issue mentioned regarding the bridge rectifier melting. Does anyone have more information on this?


So far there hasn't been a definitive response about this. I don't see how it could destroy the rectifier, but the schematic says it is an "intelligent" rectifier. It must be an electronic control rather than just a diode bridge. If, as posted, it destroys the rectifier by removing the N-G bond wire, then perhaps disconnecting the rectifier and using an external battery maintainer would bypass that issue.


MetaCipher said:


> I did reach out to support at Firman and they stated the mod isn’t supported based on warranty, NOT on the technical side.


Yeah, some manufacturers don't like to tell you how to modify the gen from the factory config so as not to incur liability. Other manufacturers freely tell you how to remove the N-G bond. Having more than one N-G bond in the system will result in current flowing on the safety ground wire. Current takes ALL paths back to the source, so there is no way to prevent current flowing on the ground wire if bonded at the house panel and the gen. Put the gen under an unbalanced load condition and then use a clamp-on meter to measure the current on the neutral and ground wires...they will be close to identical.


----------



## MetaCipher (6 mo ago)

I am going to attempt to reach out to Firman again, perhaps I'll reach someone else and get a better answer regarding lifting the neutral and how it affects the rectifier. I am going to also try to get a specific part number of the rectifier, and perhaps find more information about it online (being "intelligent" as GenKnot mentions vs. a diode bridge).

I am also curious now based on macdenewf's comment of when and why the code was changed, but I agree safety first.


----------



## pipe (Jun 27, 2021)

bvedpat said:


> ..converted Firman to floating neutral.











Remove Neutral from Frame Firman T07571







www.youtube.com


----------



## MetaCipher (6 mo ago)

pipe said:


> Remove Neutral from Frame Firman T07571
> 
> 
> 
> ...


This is interesting. Based on the comments from the author of the video he had no issues with his bridge rectifier and it’s the same model referenced earlier in this thread. I wonder what the difference is?

My Firman h07553 looks exactly the same on the generator motor (also of note, the white short cable can be removed entirely if desired).


----------



## GenKnot (Dec 20, 2021)

MetaCipher said:


> I am also curious now based on macdenewf's comment of when and why the code was changed


He is possibly referring to the change made in NEC 2008 pertaining to the acceptable grounding methods at buildings or structures supplied by a feeder or branch circuits from a grounded service located at another building or structure supplied from a common service. A subpanel is an example...you do not make a N-G bond there so as to avoid objectionable current on the ground wire. 








Two Buildings – Common Service, Grounding Requirements







iaeimagazine.org


----------



## bvedpat (7 mo ago)

MetaCipher said:


> This is interesting. Based on the comments from the author of the video he had no issues with his bridge rectifier and it’s the same model referenced earlier in this thread. I wonder what the difference is?
> 
> My Firman h07553 looks exactly the same on the generator motor (also of note, the white short cable can be removed entirely if desired).


I called Firman but got a same response on N-G bond like others. They do not recommend it but at the same time, they can not (or won’t) say what impact it may have. I wish they had clear steps like Champion to remove N-G bond. The jumper and schematic has no big difference and it is super simple to remove N-G bond.

i also asked them directly on the functionality of that intelligent rectifier and what will happen if I unplug the rectifier, the person I was talking to did not seem too technical and simply said “it needs to be there for the generator to function correctly”.


----------



## GenKnot (Dec 20, 2021)

I hadn't noticed until now that a photo of the rectifier was uploaded by DL41 in post #15. It is indeed a circuit board in lieu of just a bridge rectifier. That probably explains the "intelligent" name it is given on the schematic. It still doesn't explain why disconnecting the N-G bond on the gen would harm it.

The Brown wires are AC input, Green/Yellow is *-*, and then Red is *+* output.










bvedpat said:


> simply said “it needs to be there for the generator to function correctly”.


Well, that's not exactly a wrong answer as the battery will run down without some manner of recharging it. But, of course, your question was about what happens to the rectifier if the N-G bond is removed.


----------



## macdenewf (Sep 3, 2021)

GenKnot said:


> He is possibly referring to the change made in NEC 2008 pertaining to the acceptable grounding methods at buildings or structures supplied by a feeder or branch circuits from a grounded service located at another building or structure supplied from a common service. A subpanel is an example...you do not make a N-G bond there so as to avoid objectionable current on the ground wire.
> 
> 
> 
> ...


Correct. I actually though the nec change on single GN bonds was 1999 though. But not a code expert.
I do have a floating neutral gen and a grounded neutral. I’m going to connect them both up and truly see if I can detect current on the ground.


----------



## OrlyP (Oct 19, 2021)

I'm willing to bet that "intelligent" bridge rectifier is just a fancy name for a voltage regulator. It basically charges the battery and supplies power to the fuel cut solenoid (when triggered), as well as the generator control box/module.

I can't imagine a scenario wherein removing the N-G bond could have an effect on this regulator, much less destroy it. The DC ground path should still work in this case, regardless of whether or not it's tied in to the Neutral circuit. The only reason it can burn up is if a voltage differential is introduced as a result of removing the bond. But again, I don't see how that's possible.


----------



## MetaCipher (6 mo ago)

GenKnot said:


> I hadn't noticed until now that a photo of the rectifier was uploaded by DL41 in post #15. It is indeed a circuit board in lieu of just a bridge rectifier. That probably explains the "intelligent" name it is given on the schematic. It still doesn't explain why disconnecting the N-G bond on the gen would harm it.
> 
> The Brown wires are AC input, Green/Yellow is *-*, and then Red is *+* output.
> View attachment 12206
> ...


I left a comment on the Youtube video posted earlier, hoping the owner will respond to see if his bridge rectifier still doesn't have issues. I am wondering if DL41's was a weird fluke?

This is off-topic from the N-G bond discussion, but worth noting for others who may find this thread trying to setup a portable generator for whole-house emergency backup power. Be sure to adjust the governor on the motor itself to set the appropriate frequency to help minimize issues (on my Firman it's a silver screw near the governor spring loaded arm). I checked mine running idle and then under load. These Firman's have a high THD, so it's more of a "set it the best you can". The Firman's have a digital readout to check frequency, other generators may require a tool.


----------



## MetaCipher (6 mo ago)

With the risk of destroying the generator and voiding my warranty being too much, I've decided to look into an Inverter Generator that will provide sufficient power (to avoid THD issues) along with allowing the neutral to be floating. For those of you who may find this thread in the future this is what I am considering at the moment:






9000-Watt Open Frame Inverter with CO Shield® - Champion Power Equipment


Powering Your Life




www.championpowerequipment.com





Champion has support with videos for lifting the neutral bond (very simple), the THD is low, run-time is decent, it has a 50A hookup (which I need), it's quieter and price point isn't too much more.


----------



## GenKnot (Dec 20, 2021)

👆 Sounds like a good plan to me.

I have an older Champion (2008 model) non-inverter that has served me well. I recently bought a WEN GN625i that is an inverter unit. The waveforms on it are better looking than my grid power...I'm very happy with it. I had to change to the WEN because my old Champion had too much THD to run my new gas furnace blower. The Champion inverter should have a comparable high-quality sinewave too.


----------



## BillR (6 mo ago)

I'm monitoring this thread regarding the issue of converting a Firman generator, T08072 in my case, from bonded to floating neutral. My setup is a manual interlock switch on my panel, and a 50amp plug for connection to the generator. 
Initial testing works well on natural gas, which I plan to use for partial home backup. I like the option of a manual transfer switch and I pick which circuits/devices I want. 
I would like to have the safest setup possible, so a single bonded connection in the main panel and a floating neutral at the generator is the setup as I understand it. 
My son-in-law, an electrician, installed my 50amp setup and confirmed there should be only one neutral ground point, and should be at the main panel. He really could not comment on the Firman generator changing to floating neutral causing any damage in the generator. 
Hearing from a few users that they have made the change to the Firman generator with no damage to the regulator would be welcome.


----------



## GenKnot (Dec 20, 2021)

BillR said:


> Hearing from a few users that they have made the change to the Firman generator with no damage to the regulator would be welcome.


Yes, it would be good to hear that the N-G bond can be disconnected without frying the voltage regulator on the unit. Unfortunately, no one has said that is the case. So, the jury is still out!


----------



## Wescopc (6 mo ago)

tabora said:


> Look in your Owner's Manual at the wiring diagram (page 37, I believe). Near the AVR there is a jumper that's tying the Neutral to the Ground. Remove it and you've floated the neutral. I've circled the jumper in red below.
> View attachment 9811
> 
> It probably looks something like this:
> View attachment 9812


I just disconnected the Neutral from ground as per tabora. 
Works great - no overheating/smoke from Bridge Rectifier. Charging battery.
So far all is good.
Bob


----------



## GenKnot (Dec 20, 2021)

Wescopc said:


> I just disconnected the Neutral from ground as per tabora.
> Works great - no overheating/smoke from Bridge Rectifier. Charging battery.
> So far all is good.


Thanks for that feedback!
NOTHING should happen to the rectifier (aka voltage regulator) as a result of floating the neutral based upon examining the schematic.
It does not explain what happened to DL41's gen because he smoked his voltage regulator assembly. It could be that his unit has an unknown wiring error somewhere. Who knows?!


----------



## MetaCipher (6 mo ago)

Wescopc said:


> I just disconnected the Neutral from ground as per tabora.
> Works great - no overheating/smoke from Bridge Rectifier. Charging battery.
> So far all is good.
> Bob


Good to know! I would also add that the author of this video here (Remove Neutral from Frame Firman T07571) states he still has no issues, but he plans to test further.

For me personally, I did decide to go with the Champion unit above.


----------



## OrlyP (Oct 19, 2021)

GenKnot said:


> Thanks for that feedback!
> NOTHING should happen to the rectifier (aka voltage regulator) as a result of floating the neutral based upon examining the schematic.
> It does not explain what happened to DL41's gen because he smoked his voltage regulator assembly. It could be that his unit has an unknown wiring error somewhere. Who knows?!


Or the cause was totally unrelated and it was just a coincidence that the last thing he did was to remove the N-G bond when it happened.


----------



## GenKnot (Dec 20, 2021)

But he did it at least twice. See post #15.


----------



## Arc41 (5 mo ago)

Was the generator running off line or connected to a home in which case the neutral ground connection would be restored. Still very confusing I have remove the link on mine but have yet to see how the voltage regulator reacts to this new configuration/


----------



## GenKnot (Dec 20, 2021)

Arc41 said:


> Was the generator running off line or connected to a home in which case the neutral ground connection would be restored. Still very confusing I have remove the link on mine but have yet to see how the voltage regulator reacts to this new configuration/


The N-G bond connection will not affect the output voltage or frequency if that is what you are wondering about.


----------



## Arc41 (5 mo ago)

No I was concerned that the voltage regulator or rectifier would overheat without the neutral/ground link either through the hardwired link or through the service connection, which seemed to be the result in previous posts.


----------



## GenKnot (Dec 20, 2021)

Arc41 said:


> No I was concerned that the voltage regulator or rectifier would overheat without the neutral/ground link either through the hardwired link or through the service connection, which seemed to be the result in previous posts.


Oh, okay. Fortunately, only one person has reported an issue with that happening. I think it must be an anomaly with DL41's gen.


----------



## Arc41 (5 mo ago)

Yes hope that's the case will give it a try. It's a holiday here in Canada today so will wait until less activity.


----------



## Gus01 (5 mo ago)

GenHappy said:


> I recently purchased a Firman T07571 Tri-fuel 7500/9400 watt generator from Costco.
> 
> I also installed a Square D by Schneider Electric QO1DM10030TRBR 30-Amp Generator Main Breaker Outdoor Manual Transfer Switch.
> 
> ...


Hi
I have the same situation as yours powering my house as a backup thru a Siemens Generator sub panel. Did you figure out how to convert the Firman T07571 generator to floating neutral? What about the rest of the discussion about it overheating the rectifier when this is done?
Thanks
Gus


----------



## GenKnot (Dec 20, 2021)

Gus01 said:


> Did you figure out how to convert the Firman T07571 generator to floating neutral? What about the rest of the discussion about it overheating the rectifier when this is done?


What more can be said about those two things that hasn't already been answered in the thread? Did you read the entire thread?


----------



## Columbotrek (11 mo ago)

This thread addresses the rectifier issue pretty well. My takeaway is if the ground neutral bond is disconnected, do not start this generator without either being connected to the house service panel or making the use of a neutral to ground bonding plug in one of the generators unused outlets. Either would restore the N/G connection and the Generator could then be safely run. As to why the smart rectifier burned up, could it be the designer was relying on the chassis to provide a path to the neutral for a reference thus saving the use of a wire?


----------



## GenKnot (Dec 20, 2021)

Apparently, nothing bad will happen to the rectifier if the N-G bond is removed as reported by the user in post #59. Also, the author of the referenced video below didn't report any issues either. The situation with DL41 must be an anomaly.

How to remove the N-G bond...









Remove Neutral from Frame Firman T07571







www.youtube.com


----------



## Arc41 (5 mo ago)

Now have another problem with my Firman tri fuel gen it will not start on NG. Red light comes on but not starting. I checked the gas shut off solenoid and there is no power to it, assume it should be powered when LPG or NG is selected ...any thoughts


----------



## Aventinus (5 mo ago)

I believe the better approach to this problem is to continue using a four connector cable from the generator to the inlet box on the house, and using the generator ground to ground out the inlet box only. That said I would leave the ground connector of the cable from your breaker box to the inlet box floating. This will provide fault safety for the inlet box, and by not connecting the breaker panel ground to the inlet box or generator ground, you will maintain a single ground in the system and still be protected by the always connected neutral and the single existing house ground. Yes this will be a longer path, but you'll still have only one single path for fault protection which is important. Having multiple grounds and paths through other wiring schemes can create what are called Ground Loop currents and can present noise and other issues for devices in the home. This approach also has the side benefit of maintaining the safety Integrity of the generator in the rear event you decide to use it with an extension cord to do something on the outside of your home or property.


----------



## GenKnot (Dec 20, 2021)

Aventinus said:


> I believe the better approach to this problem is to continue using a four connector cable from the generator to the inlet box on the house, and using the generator ground to ground out the inlet box only. That said I would leave the ground connector of the cable from your breaker box to the inlet box floating.


Wouldn't meet code for *Not a Separately Derived System*. The grounding conductor must be continuous from the source (the gen) to the house loads.


----------



## Ida (5 mo ago)

1--In regards to posts #2 and #4, where the ground wire in the cord is basically removed, and you use this short, 1 foot, modified cord between the generator and the main cord. What are the thoughts on the merit of this solution? Seems simple. Is it safe and effective?
2--In regards to the instances of the rectifier smoking/melting: does this happen in a minute, an hour, many hours?
3--On my new Firman T07573, there is a yellow wire with a green stripe screwed on the bottom of the metal frame of the engine, and it is connected to the bottom crossmember of the frame of the generator. It is wide open exposed, and there is nothing else connected to it. Is this a ground wire? If so, it would be extremely easy to disconnect.


----------



## GenKnot (Dec 20, 2021)

Ida said:


> 1--In regards to posts #2 and #4, where the ground wire in the cord is basically removed, and you use this short, 1 foot, modified cord between the generator and the main cord. What are the thoughts on the merit of this solution? Seems simple. Is it safe and effective?


It is best to use a bonding plug if you want the ability to easily reconnect the N-G bond if you need to do so temporarily. Search Google for "generator bonding plug" and look at the images. You can buy them premade, or make your own by just connecting neutral and ground in plug.


Ida said:


> 2--In regards to the instances of the rectifier smoking/melting: does this happen in a minute, an hour, many hours?


It apparently does not happen.


Ida said:


> 3--On my new Firman T07573, there is a yellow wire with a green stripe screwed on the bottom of the metal frame of the engine, and it is connected to the bottom crossmember of the frame of the generator. It is wide open exposed, and there is nothing else connected to it. Is this a ground wire? If so, it would be extremely easy to disconnect


That is frame to alternator bond. Do not remove it. It is not the N-G bond.


----------



## GenKnot (Dec 20, 2021)

One more thought about your first question...
Do not use a cord with the ground disconnected/removed. If you do not want/need the N-G bond connected, then disconnect it properly at the gen.


----------



## Ida (5 mo ago)

Thanks for your responses.
I understand (I think) how to disconnect the white wire at the back of the motor to un-bond the generator, but I was pausing at this due to issues I've read about voiding warranties, melting rectifiers (possibly), Firman saying not to do it, etc.
Would the bonding plug work, without the above concerns? If so, that sounds like the easiest, most easily reversible solution.
So, to make a bonding plug, you just get a 30 amp 4 blade twist lock plug, and connect the neutral wire and the ground wire to the same terminal? Ground = green; and neutral = white, on the same screw in the plug?


----------



## GenKnot (Dec 20, 2021)

Ida said:


> I understand (I think) how to disconnect the white wire at the back of the motor to un-bond the generator, but I was pausing at this due to issues I've read about voiding warranties, melting rectifiers (possibly), Firman saying not to do it, etc.
> Would the bonding plug work, without the above concerns? If so, that sounds like the easiest, most easily reversible solution.


Only one person (DL41) reported an issue with his rectifier burning up. The others that have removed the N-G bond at the gen have not reported the same results. There seems to be something wrong with DL41's gen that is causing this. As for Firman saying not to remove the bond, I would take that with a grain of salt. A lot of the manufacturers don't want to tell you how to modify their gens from the factory configuration while other manufacturers freely tell you how to remove the N-G bond. Champion is an example of a manufacturer that tells you how to remove the N-G bond to modify the gen to a floating configuration...








Disconnecting the Neutral Bond to Frame


For certain generator applications, a qualified electrician may recommend removing the neutral bond to the generator frame, resulting in a "floating neutral." Feeding electrical power to a house thro…




help.championpowerequipment.com




A bonding plug is used by many portable generator users to reestablish the N-G bond when using the gen not connected to the house. This puts the gen back into the factory bonded condition. When the gen is connected to the house, the N-G bond is established at the house breaker panel. You would not use the bonding plug when the gen is connected to the house.


Ida said:


> So, to make a bonding plug, you just get a 30 amp 4 blade twist lock plug, and connect the neutral wire and the ground wire to the same terminal? Ground = green; and neutral = white, on the same screw in the plug?


You can do it with either a twist lock plug or just a standard 120V plug. You would jumper ground over to neutral...no other wires connected.
With the cover off, it would look something like this...


----------



## Arc41 (5 mo ago)

Looks the idea of the bonding plug is the best solution for this Furman gen something really strange going on with this design.


----------



## OrlyP (Oct 19, 2021)

Arc41 said:


> Looks the idea of the bonding plug is the best solution for this Furman gen something really strange going on with this design.


I think the bonding plug does exactly the opposite of what this thread is about (which is how disconnect the Neutral-Ground bond).


----------



## Arc41 (5 mo ago)

I think this the process 
1 remove the neutral/ground link
2 use a neutral/ground plug when not connected to the house service
3 remove neutral/ground plug when connected to the house service.
This should satisfy the generator for a linked neutral/ground condition for whatever reason it needs it.


----------



## GenKnot (Dec 20, 2021)

Arc41 said:


> I think this the process
> 1 remove the neutral/ground link
> 2 use a neutral/ground plug when not connected to the house service
> 3 remove neutral/ground plug when connected to the house service.
> This should satisfy the generator for a linked neutral/ground condition for whatever reason it needs it.


No reason for that not to work okay! 👍


----------



## Arc41 (5 mo ago)

Yes there does seem to be a problem running this generator without a neutral/ground link my regulator has apparently failed without a link of some kind. In my case I removed the link and tried to start on NG and it would not start as the gas shut off solenoid was not getting power.
Firman said the regulator has failed? Which means just cranking should generate sufficient Voltage to hold in the gas lock lockout solenoid. They are sending me a replacement solenoid which makes me concerned that is after all a design issue of some kind.


----------



## tabora (Sep 6, 2018)

Arc41 said:


> I removed the link and tried to start on NG and it would not start as the gas shut off solenoid was not getting power.


Yes, I had mentioned that way back in post #17...


tabora said:


> I agree, although it looks like that 12V supply is used for the fuel cut solenoids, too...





Arc41 said:


> makes me concerned that is after all a design issue of some kind.


Yes, I'm going with that... Removing the bond should not be causing these issues.


----------



## Arc41 (5 mo ago)

Made an error it's the regulator that they are sending me which makes more sense


----------



## GenKnot (Dec 20, 2021)

Arc41 said:


> Made an error it's the regulator that they are sending me which makes more sense


The voltage regulator right?

If you were using the process you posted in #83, then you had an N-G bond. So something's not making any sense.

If there is a design issue causing a problem with removing the N-G bond, then it must not be consistent across the units being shipped because other people are not having this problem.


----------



## Arc41 (5 mo ago)

Is there a circuit diagram for the tri fuel control board for the Firman tri fuel gen . Not in the manual and the service tech dosnt seem to have any ideas?
Anybody?


----------



## DaveG (5 mo ago)

Arc41 said:


> Is there a circuit diagram for the tri fuel control board for the Firman tri fuel gen . Not in the manual and the service tech dosnt seem to have any ideas?
> Anybody?


This is what my manual shows for the Firman T07573 and is also available on www.firmanpowerequipment.com.

I recently purchased the T07573 and will be testing by removing the Neutral Bonding at the generator and confirm the LP still works or not.


----------



## GenKnot (Dec 20, 2021)

DaveG said:


> This is what my manual shows for the Firman T07573.....


Yes, that is similar to the OP's T07571.

The mystery seems to be that some people are having the voltage regulator (aka intelligent rectifier) burn up when the N-G bond is removed. Others seem to have no issue. What might clear it up is finding a schematic of the dual fuel module.


----------



## DaveG (5 mo ago)

DaveG said:


> This is what my manual shows for the Firman T07573 and is also available on www.firmanpowerequipment.com.
> 
> I recently purchased the T07573 and will be testing by removing the Neutral Bonding at the generator and confirm the LP still works or not.


I removed the white jumper wire at the end of the "alternator" that was documented above and tested to make sure the Green wire ground was no longer bonded to Neutral.
Connected to NG source and set the switch to NG ( not Propane ), turned the front switch to NG/Propane ( not gasoline ) and pressed start. At first, I thought it was not going to work as it cranked for 5-sec or more. On the second try and choke ON, it fired up and ran just fine - NO SMOKING PARTS !

Looking back, the schematic does not show NG that I could see because electrically there is no difference between the two. The only thing you do depending on if the source is NG vs Propane is to turn a valve that is after the fuel regulator and before the carburetor. I would say this is another successful change from bonded Neutral to Floating so I can now attach to the House main and only bond neutral at the panel. I am not using a transfer switch, but a mechanical interlock that only allows you to energize the panel from the generator source if the MAIN is OFF. The interlock also makes you turn off the Solar breaker too so if during the day my solar panel will not turn back on when the generator energizes the panel.


----------



## bandergenny (5 mo ago)

DaveG said:


> I removed the white jumper wire at the end of the "alternator" that was documented above and tested to make sure the Green wire ground was no longer bonded to Neutral.
> Connected to NG source and set the switch to NG ( not Propane ), turned the front switch to NG/Propane ( not gasoline ) and pressed start. At first, I thought it was not going to work as it cranked for 5-sec or more. On the second try and choke ON, it fired up and ran just fine - NO SMOKING PARTS !
> 
> Looking back, the schematic does not show NG that I could see because electrically there is no difference between the two. The only thing you do depending on if the source is NG vs Propane is to turn a valve that is after the fuel regulator and before the carburetor. I would say this is another successful change from bonded Neutral to Floating so I can now attach to the House main and only bond neutral at the panel. I am not using a transfer switch, but a mechanical interlock that only allows you to energize the panel from the generator source if the MAIN is OFF. The interlock also makes you turn off the Solar breaker too so if during the day my solar panel will not turn back on when the generator energizes the panel.


Glad to hear this worked. I had an interlock system installed last year unbeknownst to me the issue of having a NG bond. After doing a lot research I found this thread.


----------



## bvedpat (7 mo ago)

Today I tried removing N-G bond on my firman T07571 and did not seem to have issues. I mean the generator started as normal, I let it run for 15 mins and did not see any smoke or anything.

The process followed is similar to 




i am not sure why one of the members faced issues with bridge rectifier burning. But I did not see any of these issues.


----------



## SouthernSteve (4 mo ago)

I lifted my NG bond on my T07571 several years ago to be able to run it through my service panel with an interlock kit. I ran it that way for about 30 hours all together through a power outage after a hurricane in 2019. No issues at all.


----------



## bandergenny (5 mo ago)

What fuel source did you use


----------



## SouthernSteve (4 mo ago)

bandergenny said:


> What fuel source did you use


Gasoline.


----------



## bandergenny (5 mo ago)

SouthernSteve said:


> Gasoline.


Good to know. I think the concern has been that the electronics that control being able to use LPG or CNG. Would you be able or have you tested using either of those fuel sources?


----------



## SouthernSteve (4 mo ago)

bandergenny said:


> Good to know. I think the concern has been that the electronics that control being able to use LPG or CNG. Would you be able or have you tested using either of those fuel sources?


I actually have used the genny on LPG since then, but that was under no load. Strictly testing that it operated on propane. I ran it for at least 5 minutes. I have also used it since then with gasoline without problem.


----------



## bvedpat (7 mo ago)

bandergenny said:


> What fuel source did you use


My fuel is natural gas and it ran 15 mins during the test period.


----------



## bandergenny (5 mo ago)

bvedpat said:


> My fuel is natural gas and it ran 15 mins during the test period.


This is great to hear. I am most likely going to unbond my generator as well and then buy a bonding plug when not connected to my house


----------



## tb12 (4 mo ago)

Unbonded neutral and ran test on NG for about 20 minutes can report I had no issues.


----------



## bandergenny (5 mo ago)

tb12 said:


> Unbonded neutral and ran test on NG for about 20 minutes can report I had no issues.


Thank you Tom, amazing how you had time to do this after beating the cowboys.

Do you or anyone else on this thread have a recommendation for a NG bonding plug?


----------



## SouthernSteve (4 mo ago)

bandergenny said:


> Thank you Tom, amazing how you had time to do this after beating the cowboys.
> 
> Do you or anyone else on this thread have a recommendation for a NG bonding plug?


Just find a cheap replacement plug. It doesn't matter what kind really. Take the cover off of the plug and install a small piece of copper wire (size #8 would be fine) between where the neutral and ground wires would go. Put the cover back on and you have a bonded plug. Or you could order one from HERE.


----------



## thevine (23 d ago)

Would connecting the T07571 frame directly to the ground rod of the house solve the problem?


----------



## GenKnot (Dec 20, 2021)

thevine said:


> Would connecting the T07571 frame directly to the ground rod of the house solve the problem?


There are several things being discussed in this thread, so to which "problem" are you referring?


----------



## thevine (23 d ago)

GenKnot said:


> There are several things being discussed in this thread, so to which "problem" are you referring?


I know, ask a dumb question and... But I'm talking about the problem of double grounded neutral. I am basically grasping at straws, as a last ditch effort, before facing the fact that I am probably going to have to switch the neutral wires in my box. I am not confident about separating Neutral from the ground on the T07571 via what I can gather from the problems encountered in this thread. I tried the easy option of just disconnecting the ground wire from the frame. Starter motor did not work and throttle control was lost... Looks like just about everything in this GEN is grounded to the frame. So... any suggestion(s) you might have would be appreciated.


----------



## GenKnot (Dec 20, 2021)

thevine said:


> So... any suggestion(s) you might have would be appreciated.


Well, I wish I had a direct answer to your question about whether or not to disconnect the bond. It seems that some people have done it without problems (such as post #102) while others had issues. So, if you disconnect it and the rectifier lets out smoke, then call Firman and have them ship a new one to you on their dime. It is ridiculous that you cannot break the N-G bond on a portable gen without causing a problem.

I can tell you that a ground rod is not the answer...if that helps.


----------



## Rene (Feb 5, 2021)

Adding my experience with Firman T07571. Had a interlock solution installed by a licensed electrician. I asked the electrician whether I should break the bond on my generator and he said no he did not recommend that. We didn't get into a lengthy discussion but the gist was that it wasn't necessary. I am not suggesting or an advocate of one or the other. Anyway Ida hit and my power was out for a week. I ran the T07571 on NG for the entire week powering a max of around 4k watts of appliances. Most notable was a room AC, microwave, toaster oven and others (not all at the same time). I had zero issues.

However I have always felt like breaking the bond was a better choice but with reading what DL41 experienced I never wanted to risk that since it ran fine with the bond. Now I am considering using the bonding plug as a solution as I always perform my maintenance runs disconnected from the house and would use the bonding plug for those runs.

One question on the plug, does it matter whether you use it on a 120 GFCI protected outlet?


----------



## GenKnot (Dec 20, 2021)

Rene said:


> installed by a licensed electrician


Electricians don't always understand how to install a portable generator to a house panel. Much of that is due to all the confusing code changes that have been made over the years...so not necessarily their fault.

The N-G bond at the gen must be broken when connecting it to a house panel where the N-G bond already occurs. Otherwise you have objectionable current on the ground wire. The exception would be if you install a disconnect that breaks the neutral wire. The above video (post #108) covers all of that. Also, see this video:








Rene said:


> One question on the plug, does it matter whether you use it on a 120 GFCI protected outlet?


No. The N-G bond is reestablished for the gen when connected to the house panel. Also, GFCI outlets work without a ground wire (that sounds weird, but Google it).


----------



## thevine (23 d ago)

Thank you! All things considered, I think I am just going to do it the way I usually do, the hard way. It will take time and effort but if I switch the neutral in the service box at least I will be able to finally put this behind me once and for all. Next time I will do my research before rather than after I do a project. ha ha, It is on my bucket list anyway.


----------

