The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!


2017 NEC and Related
2017 NEC
Now Available!

Recent Posts
Parking lot pole light swap....
by gfretwell
10/24/16 08:46 PM
International Wire Colour Codes
by Tjia1981
10/23/16 12:08 PM
Son of Sparky
by HotLine1
10/20/16 07:43 PM
Speaking of Plugmold ...
by gfretwell
10/17/16 02:37 PM
Broken battery charger? Check for cobwebs!
by gfretwell
10/17/16 02:30 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 14
HotLine1 7
ghost307 7
renosteinke 6
Potseal 4
Who's Online
0 registered (), 252 Guests and 5 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#16462 - 11/11/02 07:01 PM Portable generator hookup
Electricmanscott Offline

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.

Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

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

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.


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

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.


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


ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals