InPhase277

I bid a service swap recently for upgrading from two 100 A services to two 200 A services on 4 duplex units. The customer didn't want to use a meter pack, for some reason. Anyway, I figured the service like a 400 A, and used the smallest service entrance conductors allowable by the NEC, 400 kcmil copper, with 2/0 copper to each meter socket from a trough overhead.

I got the job, built one service and had it inspected. Today the POCO guy comes out and sweats and wrestles and curses the "Big Ol' Wire" we had coming from the riser. I said "sorry buddy, that's the smallest wire we could get away with." He asked why that was, and I said the NEC says so.

He told me that they (the POCO) allow that kind of service to be fed with 4/0 copper. Of course, that would save me a bundle on the other three services, but the NEC says I have to use 400 kcmil minimum. So what would you guys do, use the POCO spec, or the NEC?

BBQ

If the conductors are on the customer side of the service point you must follow the NEC.

That said it sounds like these conductors supply more than one service disconnecting means if that is the case the NEC only requires the conductors to be rated as high as the calculated load not the total of the service disconnects.

InPhase277

The thing is there was no service calc. The reason being the customer simply wanted to upgrade the outside without upgrading the inside. In other words, the old 100 A panel was left in place and fed from a 100 A breaker in the diso outside. They wanted to capacity to put 200 A panels in in the future.

I figured the safest way to go would be with 400 A service SEC's, since we can't calculate a "future load". Since I bid and won the job using 400 CU, I feel that I should just keep using it, but the POCO douche had me wondering if I should just drop to 4/0 since they allow it. What would you do?

480sparky

POCOs aren't bound by the NEC. That's how they 'get away' with feeding a 200a service with #2.

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woodchuck2

Hmmm, an older post but around here when we have something like this in question i just contact a planner from the POCO to see what their opinion is and then call my inspector to see if he will accept the planners opinion. Most of the time the inspector will follow what the POCO recommends.

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