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How is generator 10-3 wire & backfeed breaker connected at panel under an interlock kit setup

I have a Champion 7K Watt-30 amp  generator and plan to install an inlet outside on the house with the 10-3 wire running between  the floor jopists to my 1983 SquareD QO electric panel (200AMP service)


I purchased a standard SquareD 30 AMP 2 pole circuit breaker to serve as the backfeed breaker as the interlock  kit includes the retaining bracket.


I see there are so called  generator "backfeed breakers" on the interlock website that seem to differ from a standard breaker only by the addional two screws it has to secure the breaker... to the panel?... but the website says it is optional to purchase.  So is using the std breaker and retaining bracket sufficient?


Do I wire the breaker as usual, i.e., 2 hot leads to the breaker and the neutral and ground each separately to the neutral and ground bars? Do I disconnect the internal ground to frame connection inside the generator?


If the neutral and ground bars are bonded together then can I attach both neutral and ground wires to either bars?


Most of the terminals on the ground and neutral bars are being utilised.  Can I double up connections in one terminal connection if there is only one wire in it now?  Or do I need a ground bar kit and how is that installed if all the terminals are occupied on the bars?






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Posted 2012-11-21T13:00:39+0000  by Wayfarersun Wayfarersun

Hello Wayfarersun,


Thanks for your question and welcome to the community!


I'm assuming your Square D electric panel is QO outside and inside...since you referred to it as 'standard'.


There is a Homeline series of Square D that is not compatible with the older QO line. I'm pretty sure it isn't but I just wanted to clarify that.


First, mount the backfeed breaker according to the manufacturer's instructions. You'll need to next connect the cable to the backfeed breaker and run it out to the generator. It's good to have a backfeed breaker, but putting in the retaining bracket won't hurt in this instance either.

Since I don't carry the Champion 7K Watt Generators at my store here in Atlanta, I can't know for sure how to hook it up other than you seeing what the instructions say on the manual for a backfeed breaker/bracket combo.


I'd rather your neutral and ground bars be separated throughout your system for each circuit you currently have, but I'd advise to buy an additional Square-D ground bar kit to give yourself a new bar and to be kept separated.


Doubling up the terminals is a big no-no, and is more than just it not being code, its about being safe.

Square D Ground Bar Kit


Most panels should have screws holes provided on them to give installation access for the new ground bar. You can choose to separate all the grounds and neutrals if you have enough wire while you are there, or simply add to what you have now.


And as always, refer to a licensed and insured electrician who specializes in local codes and generator installations to ensure the safety of your unit.


Please let us know if we can be of further assistance.


Posted 2012-11-26T22:03:10+0000  by Joseph_HD_ATL



WE built the house in CT in 1983 and the whole house was wired by a local reputable,  professional electricians outfit.


Therfore all the grounds and neutrals were connected to a common bar by the licensed electrician.   Are you saying thats agianst code? Becuase in reading in the forums that seems to be common practice though I realise that doesn't necessarily make it right.


When I said standard I was referring to the brreaker I bought at HD.  In other words I didn't but the special backfeed breaker that the Interkock Kit site sells for Sqare D QO.   Seems the only difference are 2 screws on the special breaker to secure it to the panel, other wise I guess a "standard" breaker with retaining braket/strap does the same job.


Does a new seaprate ground bar connect to the house ground (rod) or to the utility ground which is where the current bar is connected I beleive?  But in't the house ground rod somehow connected to the Utility ground anyway ?


Or does the ground and neutral bars connect only when there is a bonding bar that runs from one bar to the other.  And why is that done?









Posted 2012-11-27T03:20:56+0000  by Wayfarersun

I'm not saying that is anything against code, and since it is an almost 30 year home, it could of been originally installed without specific parameters involved separating your neutrals and grounds.


In fact, your best reference to this is talking to a licensed electrician or better yet, the lastest 2011 NEC code book.


I would at least do the 2 options above especially if this is going to be inspected.


Lots of older homes have their neutrals and grounds in the same bar. I was simply letting you know about getting an extra bar installed so to free up space inside your panel.


As for the source of the ground, I would install a ground rod and connect the bare copper groundwire outside next to the generator to give you a localized ground. 


Use that wire and carry it to the new ground bar. It is up to you if you want to separate the neutral and ground. 


Most panels should have the bonding bar as you say in the panel.


If anything, refer to the manufacturers instructions on the generator as well as the codes that will be suitable for installation.


Please update on your progress.






Posted 2012-12-03T19:56:40+0000  by Joseph_HD_ATL
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