In ,
Doug Miller typed:
In article , "Twayne"
wrote:
In ,
Doug Miller typed:
In article , "Twayne"
wrote:
In
,
typed:
On Dec 23, 11:37 pm, terry wrote:
On Dec 24, 12:56 am, (Doug Miller) wrote:

In article ,
wrote:
And the double pole brakers can (and should) be used with split
receptacles, but NEVER with different circuits physically in
different parts of the house.

Piffle. That is *not* a requirement of the U.S. NEC -- it might
be of the CEC,
I don't know, but it's definitely not a requirement here.

You need to re-read his situatioin unless you're trolling, too.


There's nothing wrong with running a 3-wire circuit from the
panel to a point some distance away, then splitting it out into
two individual circuits that go
in opposite directions.

On ganged breakers? I can't cite it, but no, that's not allowed.

Of course you can't cite it -- because (a) you don't know anything
about electricity, (b) you don't know the Code, and (c) it's not a
Code violation.

Then perhaps you can cite something. Show me an Edison ckt in the
NEC. Or even in your local code books; I'm not fussy.

Here you go. The 2008 NEC is online at
http://nfpaweb3.gvpi.net/rrserver/br...NFPASTD/7008SB

Multiwire branch circuits (aka Edison circuits) are described in
Article 210.4

EXCELLENT link, Doug! I've often searched for a cohesive presentation of the
NEC and never found it; only pieces here & there and those never allow you
to check into the outside references, etc.. I definitely appreciate it as
I'm sure others do and it definitely gives you a top-credibility rating.
It does provide verification, IMO, that one overloaded ckt on one leg and
very light load on the other, under fault conditions on the first leg, could
cause overheating and other unforeseen problems, especially in a miswired
case. In theory equal loads on each leg will result in zero current flow in
the neutral, which is as I understood it.
It does still appear though, that a fault on one leg and little load on
the other could result in substantial current flow, then adding the fault
conditions ... .

These following aren't critical questions at the moment so feel free to
ignore them if you find them intrusive:

1. One thing is confusing however, that you might be able to explain. In
Definitions (100) for Branch Ckt, Multiwire, it states that:
"... branch ckt that consists of two or more ungrounded conductors that have
a voltage between them, and a grounded conductor that has equal voltage
between it and each ungrounded conductor of the ckt and that is connected to
the neutral or grounded conductor of the system"

It _seems_ to say the voltage between the two ungrounded conductors and the
neutral will be at the same potential as the ungrounded connectors? I seem
to have a brain-freeze again! Can you clarify what that means? The
following ref to "neutral or ungrounded conductor of the system" seems to
make no sense then and obviously it has to.

2. I've never actually had my hands on a double pole breaker and Google
hasn't given me the answer to this one: Are the breakers still independent
of each other?
I don't think that makes sense so, assuming I'm right, how is it that an
overload on one isn't affected (delayed, held from tripping) by the force
the other needs to be opened? I thought maybe there was a different internal
structure somehow and they were electonically opened somehow, but I can't
find proof of that either. I did find one page (crecibility unknown) that
said both breakers operated simultaneously, but without internal electronics
of some sort I can't see how the drag from one doesn't affect the other?

Thanks again for the very valuable lead,

Twayne

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