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Hi, I'm Mike G and I'll be assisting you. Go ahead, no problem as long as the feeder is 100A.
Anytime, you're welcome. Don't forget to rate me.
What exactly are you trying to do?
If you have a 100A sub panel and need another there are other considerations.
How long is the existing feeder?
What size is it?
Is the feeder a 4 wire cable?
Is the new panel to be in the same building?
Just how many additional panels are you needing?
The feed to the new sub panel needs to be 4 wire. 2 hots, 1 neutral and 1 ground. The wire size is 2,2,4&4 Aluminum. I suggest using a 100A lug kit instead of a breaker if this is off the existing sub panel. The main for one will serve both. You may not be able to use a 100A breaker, check the label on the existing panel.
Off the main service panel you'll need a 2 pole 100A breaker in either the main panel or the sub panel being only 5 ft apart. You can use copper but you still need 4 wires per code.
Your follow up question was why not 2 wire. You need 4 wires not 2.
2 hots, 1 neutral and 1 ground.
Yes you may. The only limitation is if the label limits the size of any breaker.
That means you can install 100A breakers. Number possible is no concern.
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