Different *services*, or different *circuits* on the same service? It is
very unusual to have more than one service to a building.
When I replaced my old 60A service with new breaker box, I gutted the old
service box and used it as a big junction box with 7 or 8 circuits spliced
into the old wires. The new service box and the old box were connected
together with a short piece of RMC. The inspector said it looked good.
That was 10 years ago, so maybe the rules have changed (but I doubt it.)
My code book is 1993, so not much point in me looking it up.
Make sure your junction box has enough cubic inches for the number of
I can't find a specific restriction, but I think you'll have trouble
getting past the rule about only one service per building (with
exceptions), and if you have an exceptional case that allows multiple
services they must be clearly marked.
Are you talking about a duplex apartment that has 2 meters in a single
enclosure with separate disconnects? I *believe* that counts as one
I would assume that these are for two separate apartments? (or one
house and a basement apartment?). If that's the case then wiring from two
different "dwelling units" can not meet in the same box. I forget which
rule this was but I do recall the inspector faulting it in an apartment I
once lived in during a general inspection.
Also, you can't link neutrals or grounds between two services: It would
be pretty hard to keep bare grounds from touching each other inside a box.
For the cost of an extra junction box why go to all the trouble?
In Canada, you can't even run two circuits from the same service through
a single box _unless_ there's a mechanical separation between the two
and/or common disconnect. Ie: our main panels have two sections, one for
the main disconnect/breaker, the other for the branches. Two services would be
There's something in both codes about a service line feeding up to 6
separate "things" (panels, individual circuits etc) without needing a
common disconnect (would imply common junction box of some sort).
But downstream of other disconnects, I don't think so.
Ask the inspector.
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
The only thing I'd worry about is that someday someone may flip the breaker
on one line, think that he's cut all power to that box and get zapped by the
live line. That happened to me when working in an older building;
fortunately, I thought to check for power when I unwrapped the second line.
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