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#47417 01/16/05 05:36 PM
Joined: Mar 2004
Posts: 55
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eswets Offline OP
Member
The state I used to work it, it was common pratice for a 400amp residential service to really be a 320amp. The meter was a 320amp rated meter socket that feed 2 200amp (main breaker) panels with 2" pipes and 3/0's to each panel. I have changed to a different region, and am wondering if this is standared everywhere or if this is not the right way to do this.

#47418 01/16/05 05:43 PM
Joined: Jan 2003
Posts: 4,391
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It is fine, a 320 meter is rated 320 amps continuous, 400 amps non-continuous.

If a 400 amp service is properly sized it will not exceed 320 amps continuously.


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#47419 01/16/05 07:23 PM
Joined: Nov 2002
Posts: 267
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Member
Common practice in Mass. 320 amp continuous for a 400 amp service. 80%. I believe you have to be the full 400 amp on commercial services. Most of the electricians around here install it exactly how you explained except they use 4/0-3 SEU/AL. No pipe. Your way is much better, I guess around where I am they go the bare minimum requirements.

#47420 01/16/05 08:43 PM
Joined: Dec 2004
Posts: 46
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wirenutt.. what do you guys in Mass. run for 400amp UG services?? what would be a typical meter and panel configuration be. Thanks..ToHo

#47421 01/16/05 08:55 PM
Joined: Jan 2003
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Quote
I believe you have to be the full 400 amp on commercial services.

The only reason I can see that requirement is if you used 100% rated breakers and equipment.

A typical 400 amp breaker is only UL listed for 320 amps continuous or 400 amp non-continuous.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#47422 01/16/05 09:28 PM
Joined: Feb 2003
Posts: 687
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Thats how the 400 amp resedential are set up around here in IL. We don't call it a (2) 200 or 320 amp. Maybe more of a sales thing. Don't want to be pricing out a 320 amp when the other EC has the same set up calls it a 400 amp.

Tom

#47423 01/16/05 10:12 PM
Joined: Mar 2004
Posts: 55
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eswets Offline OP
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Tom,
Im in IL I think around your area. Suburbs of Chicago. So using a 320amp meter socket with 2/200amp panels is ok for the 400 amp service?

#47424 01/17/05 07:11 PM
Joined: Feb 2003
Posts: 687
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Member
Yep.

At the supply we just ask for a 400 amp pedistal but they know we mean 320 amp. Milbanks catolog for Com Ed only shows single phase 320 not 400 amp meter housings. Com Ed resi feeds underground are normaly 200 and 320 a. Overhead 100, 200, and 320 a.

We would only bond one panel and would run a larger water pipe ground than a single 200 a service, I think 1ott. You could do it other ways.

Tom

#47425 01/17/05 08:28 PM
Joined: Nov 2002
Posts: 267
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TOHO; Mostly the Milbank # 2448-X meter socket. One EC uses 500 kcmil xhhw. Murray also makes a unique 400 amp double main break panel that's kind of interesting. Guess it depends on your situation.

#47426 01/18/05 12:37 AM
Joined: Jun 2003
Posts: 681
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Tom
What do you mean by, "bond only one panel"?

Pierre


Pierre Belarge
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