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#85326 - 06/20/03 04:15 AM Small commercial services
RickG Offline

Registered: 07/04/01
Posts: 37
Loc: South County, R.I. USA
As far as the NEC goes, is it permissible to install 4/0 al service entrance conductors to a non dwelling service consisting of only 1 service disconnect? I thought that the minimum was 250 MCM al for this type of service. So many electricians seem to think that 4/0 is OK for 200 amp commercial. I am looking for other opinions & code references. Thanks,

2014 / 2011 NEC & Related Books and Study Guides
#85327 - 06/20/03 07:04 AM Re: Small commercial services
Ron Offline

Registered: 03/13/02
Posts: 577
Loc: White Plains, NY
Table 310.15(B)(6) can only be used for dwellings. A 200A commercial service must be from table 310.16, 250 kCMIL AL minimum.

#85328 - 06/20/03 01:45 PM Re: Small commercial services
engy Offline

Registered: 06/25/02
Posts: 15
Loc: Minnesota
4/0 Al 75deg is rated at 180A
Round 'er up to 200A.
4/0 must meet article 220 load calc.

#85329 - 06/20/03 05:39 PM Re: Small commercial services
iwire Offline

Registered: 01/05/03
Posts: 4343
Loc: North Attleboro, MA USA
240.4(B)Allows us to round up to the next standard size breaker under 800 amps.

Before doing this read the article yourself to see if you meet the 3 requirements.

For this service you should be all set.
Bob Badger
Construction & Maintenance Electrician


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