# CAT RP7500e - is this the neutral bond jumper?



## Pickle Rick (Aug 8, 2020)

I'm 99.99% sure that I found the jumper that bonds the neutral to ground, but I'm not an electrician and find the schematic confusing. (And it has errors in it like "spark plub" so who knows if it's even trustworthy?)

My multi-meter says this is the correct wire to disconnect for using this unit as emergency home backup via an interlock kit. When I disconnect it, continuity is lost between neutral and ground as tested using the 120V GFCI receptacles. (I have ordered this so that I can easily and safely use the generator stand-alone without having to put the jumper back.)

The yellow/green jumper wire is connected to the metal housing (ground) on one end, and to a lug shared with white wire (which I assume to be neutral) on the other:










This picture better shows the white wire (to right of red) where the yellow/green jumper shares a connection.










Questions:

Can someone confirm I have selected the correct jumper to un-bond the neutral? Like I said, continuity between ground and neutral is indeed broken when I disconnect it. I'm just paranoid about starting it up and trying it without someone more experienced weighing in. Schematic is attached.
Is my best bet to disconnect the grounded end and loop it back to the same lug as the other end (shared with the white wire)? I don't want to just remove the jumper, in case it gets lost. I could tape off the ground end after disconnecting, but I kind of like the idea of just bolting it down where it can't move around from vibration. (I also don't like how electrical tape breaks down over time.)
One more picture of the whole thing, if needed:


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## ToolLover (Jan 13, 2020)

The neutral bond is the green and yellow short jumper that is connected from the ground post where the white wire is.
Remove it from both posts and retain it in case you want to reattach it.
Leave the grounding wire on the grounding post only.
I took a good look at the schematic you provided and that jumper if it is there it is well hidden. I could not find it shown.
Be sure to tighten any nuts that you loosen.


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## Pickle Rick (Aug 8, 2020)

ToolLover said:


> The neutral bond is the green and yellow short jumper that is connected from the ground post where the white wire is.
> Remove it from both posts and retain it in case you want to reattach it.
> Leave the grounding wire on the grounding post only.
> I took a good look at the schematic you provided and that jumper if it is there it is well hidden. I could not find it shown.
> Be sure to tighten any nuts that you loosen.


Thank you for confirming!


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## tabora (Sep 6, 2018)

I usually disconnect the end of the jumper where it connects to the white neutral, and then loop it to the ground post or just wrap the loose end in electrical tape. That way it doesn't get lost if you later need it for standalone use.


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## ToolLover (Jan 13, 2020)

I respect Tabora's experience about Generators but I looked at the print and in the upper left is a square that contains four terminals the are what you are looking at in your photograph.
I differ to agree with Tabors taping the terminal and leaving it in place.
The suggestion to tape the terminal can lead to vibration that can rub tape off a terminal and cause a short. The termination of the field wiring in that area can cause severe problems at a later date in the run time that might be not expected.
However you can re-terminate the G/Y wire onto the ground and leave it there as Tabors suggested and be safe.


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## Pickle Rick (Aug 8, 2020)

ToolLover said:


> re-terminate the G/Y wire onto the ground and leave it there


This is what I plan to do. If I remove it I just know it will get lost. I dislike electrical tape for the reason you mention. (Also, it makes a sticky mess after it starts to break down.)


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## tabora (Sep 6, 2018)

Pickle Rick said:


> This is what I plan to do. If I remove it I just know it will get lost. I dislike electrical tape for the reason you mention. (Also, it makes a sticky mess after it starts to break down.)


I agree! The one time I used the electric tape was on a jumper that was actually a rigid, flat piece of metal. It was rotated out of the way, but I wanted to make certain that if it ever rotated back it would not make electrical contact with the neutral connector again. With the flexible jumper, looping it to the ground lug is the way to keep it safely available.


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## Pickle Rick (Aug 8, 2020)

Done! Two minute job to loop that flexible jumper. Installing the tent took a bit longer.

I bet I won’t have a power outage for years now that I’m well prepared for one!

Thanks for the help, guys.


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## iowagold (Jan 22, 2020)

well done!
yea i like the 2 lugs on the same post or bolt idea best.
if you have room for them.
that way it is all there.
make sure you put a Lable on the plug panel of the gen stating it is un bonded for home generation use only.
do not use as a stand alone generator.


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## iowagold (Jan 22, 2020)

Pickle Rick said:


> One more picture of the whole thing, if needed:
> 
> View attachment 8168


Does any one see what is right with this pix of the cat gen head???
or did every one miss it??
lol
"it has posts and pre drilled and tapped for a puller to remove the end cap!!"
yup cat is a class act for sure!!
lol they just have a bad spell check intern working on the manual for spark plug!
grin!
good pix p rick!!
well done on the gen job!
I hope you will never need it!
but.... i am glad you have a plan!!
did you get to test run the system yet?
or are you still working on it?

lol mine is never done..
I am still tweaking on it after 15 years!!
there is always another good idea to improve on the backup system!!


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## Pickle Rick (Aug 8, 2020)

iowagold said:


> did you get to test run the system yet?
> or are you still working on it?


I gave it a very quick test:

Started it using electric start (sooo nice)
Plugged my ground tester into a GFCI outlet to show what my multimeter already confirmed for me - my generator is now floating neutral. Yay! That was an easy affair, and lots of room in there to loop the jumper back on itself on the grounded end.
Plugged in to my home's generator inlet and confirmed that my ground tester is now happy
My family were busy working/schooling, so I couldn't turn off the mains and open the interlock circuit. I'm quite sure it will work much more smoothly than my 30yr old Coleman (with 5000 PEAK watts), though.

I really like the hour/frequency/voltage meter. Frequency, especially, is a useful metric for me... I know my Coleman is running too fast because all the digital clocks in my house were gaining minutes every hour during the last outage! (On my todo list to pickup a kill-a-watt and adjust the RPMs. I'm keeping the old work horse as backup for my backup, or to lend out to a less prepared neighbor when the next storm hits.)

I have my HVAC guy coming, tomorrow, to tune up my boiler. I am going to ask him to look at my central A/C unit to see if there's any chance this 7500 watt genset could run it if a soft start kit were added. (Like, maybe just at night when everything else in the house was off except the fridge.)


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## iowagold (Jan 22, 2020)

and most of the time if you have a good fan on the a/c unit for the inside air flow
you can lock the fan on.
if that feature is not yet on your system.
now is the time to talk with your hvac guy to have it added!
nice to be able to lock the fan on during and power outage to keep the whole house air moving.
i use mine during the below zero temps to keep the air moving..
and is nice for summer super hot as you can churn the whole house if you are running one window ac unit
and want to flow it in the whole house for a bit of dry air.
and if done right at night time you can have a cooler house at least in the am hours..

check your insulation!!
I did mine back 15 years...
it had zero insulation in the attic!!
now there is r56 up there.
still in the works are the walls insulation after i get the new ng water heater in.

this place was built in 1900...
never updated on the insulation!
that attic r56 insulation paid for its self in the first 2 years!


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## Pickle Rick (Aug 8, 2020)

iowagold said:


> make sure you put a Lable on the plug panel of the gen stating it is un bonded


Overkill? Yes. Do I want to order, anyway? Also yes. 

Generator Neutral Warning Magnets


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## drmerdp (Apr 10, 2018)

I can certainly appreciate the attention to detail.


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## iowagold (Jan 22, 2020)

cat is a good company for sure!!
watch them in the next couple of years...
i bet they do a larger inverter unit!
most folks with all the y3k issues right now..
storms , fires, pandemic, civil unrest..

they are demanding better gens!
there is a gen shortage right now.
so watch for a flood of good units maybe after the first of the year in 2021.

honda is working like mad right now getting the new 2020 units made...
they are shipping ..
it is just super slow with the import restrictions..


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## drmerdp (Apr 10, 2018)

One thing I’ve noticed is that cheap gens continue to get more bells and whistles but fail to deliver on quality components.

Fancy displays, Bluetooth, elaborate colors and designs, same Honda clone engines, sub par alternators, and little to no parts availability. (disposable...)

Hopefully a company like CAT which has stood for quality can turn things around.


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## iowagold (Jan 22, 2020)

yup
all that flash stuff is ok...
but parts and real quality in the design and parts is way more important for me as well!


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