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#16462 - 11/11/02 07:01 PM Portable generator hookup
Electricmanscott Offline
Member

Registered: 01/12/02
Posts: 1478
Loc: Holden, MA USA
I have a customer that would like a manual generator setup. I planned to use one of the "Gen Tran" tranfer switch setups with six circuits. The problem is the generator receptacle is a 20A 250V three wire twistlock. The panel takes a 4 wire. I thought I'd throw this out to the vast knowledge base here and see what comes up.

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#16463 - 11/12/02 03:31 AM Re: Portable generator hookup
Trainwire Offline
Member

Registered: 03/15/02
Posts: 364
Loc: Strasburg,PA,USA
I don't know if what I did is legal or not, but I ran a four wire cord from the transfer switch back to the generator and put a three conductor plug on the generator end, and ran the green conductor out the cord grip and put a ring terminal on the end, and a stud and wing nut on the generator frame. The bigger generators have four wire outlets.

TW

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#16464 - 11/12/02 08:30 AM Re: Portable generator hookup
caselec Offline
Member

Registered: 04/14/02
Posts: 557
Loc: San Jose, CA
TW - I think his problem is that there isn't a neutral at this receptacle only 2 hots and a ground.

If that is the case I think the homeowner needs to go shopping for a different generator. I have seen many of the cheap ones that have a 20A - 250V receptacle and a 30A - 125V receptacle but not any 4 wire receptacles. Unfortunately most of the pre-built transfer switches like the one you are describing need a 4-wire connection. If the generator does have the 30A - 125V receptacle you could build your own transfer switch out of a small load center using 2 main breakers with an interlock but if you are feeding multi wire circuits this would not be a good idea. Another option is try to find a cheap auto XMFR and use this to create the needed 4th wire.

Curt

[This message has been edited by caselec (edited 11-12-2002).]
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Curt Swartz

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