Chris Lewis ) said...

According to Calvin Henry-Cotnam :

[ multiple circuits feeding a single outlet box.]

In residential installations where this has had to occur, I have never
had a problem with inspectors, and none have ever required labelling, but
I prefer to put a label (usually on the inside of the cover plate), just
in case any future work is not done by myself.

Odd.

I thought the CEC and Knight are pretty explicit about _requiring_ that
every box must be completely deenergizable by one disconnect (other than the
main of course ;-) There were some ways you could get around this, eg:

- metal barriers between the sections
- locking the boxes or area so they're not accessible by
"unauthorized persons".

Well, the code changes to the CEC 1994 explicitly allow two circiuts
on opposite poles that share a neutral to be powered by separate single
pole breakers. In other words, it would be possible to deenergize only
part of some boxes down the line.

I attended a new code seminar back then and the inspector running the
presentation discussed this to the surprise of many of the attendees.
He had to explicitly mention about being careful when circuits are on
mini/half-size breakers as it is not always clear which pole they are
supplied from.

I recall at the time the condo where I live had a few circuits wired
that way, though it was built in 1988-9. This was a code violation when
it was built, but became legal with this change in 1994.

This is why, for example, the main and branch breaker sections of
residential panels are internally segregated by metal, and usually
have separate covers.

It is one reason. Another reason, though less common these days, is that
the main section sometimes is sealed by the utility. Some utilities provide
flat-rate water heaters that must be supplied by a pair of 12 or 10 gauge
conductors that are fed from ahead of the meter. Connections to this is
made in the mains section that is later sealed.


That said, it is best to label it if it cannot be fully separated.

--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
- Napoleon
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