"Percival P. Cassidy" wrote:

On 10/09/2014 12:37 PM, Tony Hwang wrote:

125A would be the maximum size you can use (with appropriately rated
wiring), that is the max branch circuit size allowed by code for
residential services. You'll have to special order 125A breakers though
as they are not common.

What is the definition of "branch circuit"? We have a small panel in the
garage back-to-back with the meter. That has two 100Amp breakers
(ganged) from which the "main" panel in the basement is fed, and a 15Amp
breaker feeding the lights and outlets in the garage. Is everything fed
from that panel in the basement part of a "branch circuit" and limited
to 125A? E.g., IF* we got our service upgraded (I have no idea what
gauge wire is used to the meter and from the meter to the panel in the
garage) and ran heavier-gauge conductors from the panel in the garage to
the one in the basement, would we still be limited to 125A from the
panel in the basement?

* We've never tripped the 100Amp breakers, so the question is academic.

You have breaker box behind the meter, main panel is in the basement,
To protect wiring
between garage and basement. I don't think you have sub panel. Isn't sub
panel branching
out from main panel? No?

So that panel in the garage doesn't count as the "main panel"? I would
have thought that the "main panel" would be the first one after the
meter. No? (That's why I put "main" in quotation marks referring to the
one in the basement -- because I thought that technically it might not
count as the "real" main panel.)

Perce

I believe it counts as the service disconnect and thus also the bonding
location for ground and neutral. There should be a four wire connection
to the load center in the basement. The branch circuit would be the
breakers that snap into the load center and those are 125A max. The
service disconnect isn't a branch circuit so those breakers could
readily be 150A, 200A, etc. as appropriate for the load center. I've
seen 400A service split feeding two 200A load centers in residential
service before (big f'n house).