Tap rule for power connections

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Re: Tap rule for power connections

From your 400 amp breaker down.

1. You might have a code problem with the double lugging on the load side of any circuit breaker.

2. If your 250 amp load causes 400 amp breaker to trip, you'd lose power to all branch devices; however, that might be the desired result.

3. I'm not sure why you would use "green cable" for current conductors.

4. It looks as though your taps are ok for the 250 amp and 125 amp loads. The 25 amp and 32 amp load taps appear to be undersized per 240.21 B2 of 2002 NEC.

And then again, I could be wrong.
 
Re: Tap rule for power connections

Not sure the NEC applies to a control enclosure.

If the NEC did apply, the basic problem I see is that you can't "tap a tap".
Steve

[ November 04, 2005, 02:06 PM: Message edited by: steve66 ]
 
Re: Tap rule for power connections

As Steve said, you can not tap a tap.

The conductor from the 400A breaker to the distribution block needs to be rated for 400A (like 500kcmil), not the #4/0 you have listed.

If you have a choice of 400A breakers find one that has "power distribution lugs". This will prevent the tapping of a tap as well as reduce the components in your cabinet.

Foe example, Square D has a lug #PDC4LA250 that has holes for (1) #2-250kcmil, and (3) #14-#2.
 
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