1200 amp service conductor sizing

[russ]

I did an inspection on a 3 phase 208V 1200 amp service.

Three riser conduits, with four 600 kcmill conductors, from the CT to the overhead drop.

From the CT to the 1200 amp main breaker, the contractor ran three sets, of four 500 kcmill conductors.

My first thought was a violation of 240.4 (B).

After thinking about it, if this was a switch gear, with six or less switches, without a single main switch, wouldn't load calculation dictate the conductor size.

edit to add, I have to run out check back later, Thanks.

[ March 29, 2005, 05:42 PM: Message edited by: russ ]

 

[pierre]

Re: 1200 amp service conductor sizing

Russ
If the 500s are run to a switchboard buss, and there are 1-6 disconnects connected to the buss, than the size of the conductors is dependent on the calculated load. I agree with your rethinking this one through. If the 500s are terminated to a 1200 amp disconnect, than it is a violation of 240.4(C).

 

[mpd]

Re: 1200 amp service conductor sizing

240.4 (C) would not apply to a service equipment
rated switch gear with 6 disconnects, look at
230.79 and 230.80

 

[russ]

Re: 1200 amp service conductor sizing

Thank's for the replies, you're right pierre, 240 (C) not "(B)".
I just started to second guess my self, even though Iv'e always been of the opinoin that the conductors for the larger services had to be equal to or larger than the overcurrent device. (single overcurrent device, that is)

Thanks again Russ

[ March 29, 2005, 08:11 PM: Message edited by: russ ]