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#87928 - 05/04/04 01:15 PM Oversized panels supplied by existing service entry conductors
tdhorne Offline

Registered: 03/22/01
Posts: 344
Loc: Maryland, USA
I've been running into a lot of panel change outs that were done years ago in order to provide for more branch circuits with no increase in the size of the service entry conductors. One I surveyed this morning was a two hundred ampere split buss panel that was connected to a sixty ampere service entry cable. The customer is asking that the existing panel be updated to breakers. I had to give him the bad news that he was looking at a heavy up rather than a simple change out.

My question is how much of this sort of thing do others see.
Tom H
Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison

2014 / 2011 NEC & Related Books and Study Guides
#87929 - 05/04/04 02:36 PM Re: Oversized panels supplied by existing service entry conductors
Fred Offline

Registered: 04/30/01
Posts: 461
Loc: Straughn, IN 47387
I see a lot of this. 100A panels with the original 60A meter socket and #6 cloth covered SE cable risor. Most I have seen were done in the last few years by a cheap HO that was told by a realtor they had to upgrade to sell the house and the "home inspector" didn't catch it. On the other hand, I saw one this week where a lady had just purchased this house last month and had her own "home inspector out last week to check everything out. She called me because he had noted that the service conductors were the wrong size and she was afraid she had a potential fire on her hands. The panel was an ITE 150A 30 circuit Main breaker circa 1970 and in good shape. The "wrong sized" conductors were 4/0 copper. The inspector's report stated that the service entrance conductors for a 150A service should not be larger than #1 copper or 2/0 aluminum. I had a hard time convincing her it was okay to go bigger. The old ITE panel had lugs that were marked to accept 250.

#87930 - 05/04/04 07:54 PM Re: Oversized panels supplied by existing service entry conductors
djpep55 Offline

Registered: 04/24/04
Posts: 26
Loc: Crystal Lake, IL USA
If the homeowner doesn't have me fix these I report it to the POCO and local building department. It's not that I'm upset about not getting the job, but rather upset about the potential for loss of life. I don't care if I fix it or someone else does, as long as it's fixed. There are typically other violations as well...such as grounding.

#87931 - 05/05/04 08:12 PM Re: Oversized panels supplied by existing service entry conductors
PCBelarge Offline

Registered: 06/08/03
Posts: 657
Loc: Dobbs Ferry, NY, USA
The service entrance conductors have to be sized according to 230.42... the load calculated.
But... 230.90(A) Says the overcurrent protection of the service conductors cannot exceed the allowable ampacity of the service conductors.

Pierre Belarge


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