How Far Away Can You Install A 100 Amp Service

LarryFine

Re: tap rule for sub-panel

Nosotros should have asker: how far betwixt panels?

LarryFine

Re: tap rule for sub-panel

The smallest sub-console I'm familair with is rated at 125 amps. If you lot employ cable capable of the 100 amps, such equally #2 AL, then y'all have no concern, except cost, which is where altitude comes in.

How much lower than 100 amps are you considering? Every bit long equally you stay inside 1/3 of the OCP, which means a thirty-amp feeder is too small, tap rules may use.

Tap rules say "240.21(B) Feeder Taps. Conductors shall be permitted to be tapped, without overcurrent protection at the tap, to a feeder as specified in 240.21(B)(1) through (v)."

Notice it says "Conductors shall exist..." I don't know if that applies to lugs in a panel.

hillbilly

Just a hunch. If the panel that you are supplying with the tap is a lighting and appliance panel, it has to have overcurrent protection on the supply side. 408.36
steve

hillbilly

Yes they do. The point that I was trying to make is that if he was feeding a lighting and appliance panel board, it has to be protected (on the line side) past breakers or fuses having a rating not greater than that of the panel board. If he tapped off of 400A main lugs to a lighting panel, the lighting panel has to be rated at and fed with 400A, OR has to accept OC protection (on the line side) equal to or less than the rating of the lighting sub-panel.
steve