Re: sub panels when main panel is full
Originally posted by goldstar:
Bob, I'm just curious as to how you would/could make this code compliant. I believe Jes25 is talking about an existing residential installation with a main breaker panel.
This is what I think, first this is not how I would choose to do it, I was only answering the original question.
What section would apply to tapping off the lugs on the line side of a residential main breaker panel, to go to a main breaker sub panel
I run into this a lot, is it code?...... was it code?
There is no reason a single house can not have up to six service disconnects.
You have an existing service panel, nipple another panel right beside it. Tap the service conductors in the existing panel with split bolts, H-Taps, or whatever you like, run these tapped conductors to the main breaker in the new panel. Ground and bond this new panel now you have 2 service disconnects and a new empty panel.
Do the wires to the second breaker have to be sized the same as the service entrance conductors?
No, size the wires by the breaker they are feeding.
Using 230.90(A)(1)Exception No. 3 we might be adding a second 100 amp panel to a existing 100 amp service, all the conductors will be 100 amp conductors, even though the original service conductors will now have 200 amps of overcurrent protection.
Are they still considered service entrance conductors?
Yes.
Here is a common (around here) application of that exception.
200 amp service conductors in the riser, six 100 amp main breaker panels in the basement.