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#185665 - 03/23/09 06:22 PM Wire for 600A 1Phase service
Obsaleet Offline

Registered: 04/05/03
Posts: 361
Loc: Pa
Hi Guys, I am doing a 600a 1phase service and I was going to use 350kmcm in parallel, my friend from a diffrent firm is telling me they used 300kmcm for one just recently. Now I am second guessing myself, so I am turning to you all.

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#185667 - 03/23/09 07:08 PM Re: Wire for 600A 1Phase service [Re: Obsaleet]
HotLine1 Offline


Registered: 04/03/02
Posts: 6792
Loc: Brick, NJ USA
300KCMil Copper, 75 degree col is 285 amps,Based on 240.4 (B)parallel is 570 amps, next higher available is 600 amps.

300's work.

#185668 - 03/23/09 07:14 PM Re: Wire for 600A 1Phase service [Re: Obsaleet]
Yoopersup Offline

Registered: 03/04/03
Posts: 826
Loc: Michigan
If in two seperate conduits 300 kcmil is good for 285 amps at 75c. see 240.4 (b) (800 amps or less next higest breaker size) .
240.6 300 next breaker size is 600.
285 plus 285 = 570
if in one single conduit see table 310.15(B)(2)(a)
4-6 80%
570x80%=456 next higest per 240.6= 500amp.
Same Conduit would require 400 Kcmil
335x2= 670 x 80%= 536 . 240.6 next higest 600
This is with 3 wires in conduit single phase. Or
6 wires in conduit single phase.


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