Doing the electrical for a friend on his 1000 sq ft addition. Main part of the house has an existing 10 yr old 200 amp panel that is full. I was going to put a sub panel in the new addition utility room and either back feed it or just get a panel with a 100 amp main. Can I use a 100 amp breaker in the existing panel and feed the new sub panel with a 100 amp breaker or does this violate the tap rules its about a 50-75 ft run from panel to panel ?
Tony, no offense intended, but can you legally permit this work not being a licensed EC?
Roger
I guess today is just not my day. I do have a license two as a matter of fact.
N.C 14766-L since 1988
Va. 2705078514
look em up just renewed
And I let my HVAC go because it was too much headache.
I am a Project manager on Computer networks now so my Electrical knowledge may not be what it used to be. So can I do my friends a favor or do I need to call a contractor. Little bit of adevrtising for your site in Electrical contractor and now we can't even ask a question. It's all good
Tony, certainly you can ask questions.
I asked you one and you answered.
Here's another one do you have or can you access a current copy of the NEC?
As far as your original question, yes, you can feed this new panel from a 100 amp breaker and there is no limit for length of a feeder which is what you would have in this case. (not a tap)
Has anyone calculated how this additional load is going to impact the existing service?
Roger
Tony, If you utilize a 2P 100A breaker in the main panel to feed the sub panel, that's not really a tap, just a feeder circuit. You don't necessarily need a main CB in the sub panel, but it might bu useful for local isolation.
Two things to make sure of:
1. Use adequately sized feeder wire.
2. As noted above, someone should do a load calc on the entire electrical service and distribution system.
I presume your friend is getting a permit for the addition? Did he get the electrical permit also? Most building authorities will want to see this info too.
Radar
Yes they have a permit, I am already thinking it may be more than I can handle they are wanting to move the dryer onto this new panel 1.5 ton ac plus various 110vac circuits they may wind up with a 200amp feed thru at the rate things are going I really don't have the time to do it.
I might have the A/C on the main, and move some existing 110 circuits to the sub.