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Generator backup for home #199652 03/03/11 10:17 PM
Joined: Feb 2011
Posts: 56
pooL8 Offline OP
5000W Generator backup for a house, 20A 120/240 output
Tranfer Switch is 2 30A breakers
I'm using #10 (20A X 1.25) ? for all feeders
Should breaker from main panel be 30A, or 20A?

I used 30A in the past (cause I was told to), but with a 20A output from the Generator, I'm second guessing. Maybe I'm missing a rule or something.

What do yalls think?

Tools for Electricians:
Re: Generator backup for home [Re: pooL8] #199653 03/03/11 10:29 PM
Joined: Jul 2002
Posts: 8,379
Trumpy Offline
You're using circuit-breakers as a transfer switch, is that legal?
I was under the impression that a transfer switch had to be a manual change-over switch that broke the incoming mains hot and neutral conductors.

Re: Generator backup for home [Re: pooL8] #199663 03/04/11 01:27 AM
Joined: Feb 2008
Posts: 21
jackolsen Offline
Pool8 have you checked the BC Safety Authority web on Vancouver island the safety authority put on a tech talk
about back up power systems and there is a directive on this subject,you should be able to download a copy of it

Re: Generator backup for home [Re: jackolsen] #199664 03/04/11 01:44 AM
Joined: Feb 2011
Posts: 56
pooL8 Offline OP
Sweet thanks

Re: Generator backup for home [Re: Trumpy] #199665 03/04/11 02:02 AM
Joined: Feb 2011
Posts: 56
pooL8 Offline OP
The Breakers are side by side, with an interlock clip.

The TS that I am speaking of doesn't have an extra pole on the breakers for the neutrals. I was wondering about that too.

I just read that if Generator's neutral is bonded to it's own ground, then the neutrals need to be switched, but if it isn't then neutrals tie together. (I'm not entirely sure, but that's what I read).

Re: Generator backup for home [Re: pooL8] #199673 03/04/11 09:22 AM
Joined: Jul 2007
Posts: 265
wire_twister Offline
That is correct, you do not have to break the neutral, just be sure it is isolated from ground in the transfer switch. Now go and get yourself a real transfer switch, before somebody takes the interlock off your breakers and does some damage, or worse. You can get a Cutler Hammer 200 amp switch from Harbor Freight tools for around 200 here, i think its worth that much for peace of mind, not to mention liability.


Life is tough, Life is tougher when you are stupid
Re: Generator backup for home [Re: wire_twister] #199688 03/04/11 06:56 PM
Joined: Feb 2011
Posts: 56
pooL8 Offline OP
woah, that's a good price.
The one I'm eye balling is a FP from Canadian Tire. It's $250.

I haven't checked the wholesaler yet. They carry SqD and Seimens stuff.

Cool ya, thanks, it makes sense to treat the Generator like a service, or a sub-panel (with respect to neutral), depending on it's grounding.

I would like a section in the codebook that would clarify Generators.... even though all the other general rules do smile Apparently.

I asked an inspector my question about the breaker from the main panel. He said it's just like a disconnect, so 30A is fine. The branch circuit breakers will do their own job.

Now I get it all. Thanks guys... I feel taller or something.

Re: Generator backup for home [Re: Trumpy] #199689 03/04/11 06:59 PM
Joined: Feb 2011
Posts: 56
pooL8 Offline OP
By the way Trumpy, I probably should have mentioned that it is a portable Generator, with no ground. whistle


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