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
International Wire Colour Codes
by Tjia1981
Yesterday at 09:09 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
230 or 345 kV transmission lines?
by annemarie1
10/12/16 01:23 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 11
HotLine1 6
renosteinke 6
ghost307 5
Potseal 4
Who's Online
0 registered (), 159 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#18417 - 12/09/02 07:41 PM Transfer switch feeder
sparkync Offline

Registered: 10/17/02
Posts: 811
Loc: NC
I think I'm missing something..must be because I'm tired tonight... If I have a 8000 wt. generator and using 120 volts circuits it can handle 66.6 amps, and on 240 volts it can handle 33.3 amps, should not the feeder and main breaker be rated at 66.6 the maximum capacity?? I think I might be missing something here.. awfully tired I feel like this is probably a dumb question, but just can't get my head to work right, right now Is the sizing different on generators?? Thanks....Steve

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....

#18418 - 12/09/02 10:21 PM Re: Transfer switch feeder
Trumpy Offline


Registered: 07/05/02
Posts: 8532
Loc: SI,New Zealand
Sit down with a coffee, do your calc's again,
I am sure that you have missed something.
Have you figured Power Factor(Cos Phi), in to your calcs?.
How about losses?.
Let's face it, these days if you're not young, you're old - Red Green grin

#18419 - 12/10/02 05:33 AM Re: Transfer switch feeder
jdevlin Offline

Registered: 08/07/02
Posts: 402
Loc: welland ontario canada
Think double pole. 33.3 x 2 =66.6

#18420 - 12/10/02 01:00 PM Re: Transfer switch feeder
pauluk Offline

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Assuming that the generator's 120V output is split across each half of the 240V winding, then loading 4000 watts on each leg (ignoring power factor concerns) would result in 33.3A on each side of the breaker. The neutral in this case would carry no current, just as if the supply were from a xfmr.


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