Ken wrote:
RBM wrote:
"Ken" wrote in message
...
John Grabowski wrote:
"Ken" wrote in message
...
RBM wrote:
"fzbuilder" wrote in message
...

I have a 2 pole 20 amp breaker that I though went straight to my
washing machine in the garage, but upon tripping it I see my fridge
and a couple 20 amp 120v outlets in the kitchen go out too. I am
wondering if it is possible that someone has wired one side of the
breaker to go to the kitchen and one side to my washing machine. If
so, what would be the best way to tell? Thanks

Open up the panel and remove one wire from the breaker, then see
what gets turned on. Most likely you are correct, that the kitchen
outlets and fridge are on one wire, and the washer is on the
other, as that would have been the Nec legal way to do it.
Is the use of such a ganged (two pole) breaker for two separate
circuits an acceptable practice? Just curious as to why someone
would do this beside the fact it is easier to pull the wire?


A two pole breaker is now required in the 2008 code on multiwire
circuits. I think in Canada it has been required for some time.
Could you please define a "multiwire circuit?" Is it a circuit
consisting of two hot wires, such as a 220 volt one where two 110
volt are used?

As John and Wayne explained, these are circuits that share a common
neutral. There was only a requirement to use a double pole breaker if
both circuits were attached to devices in a single box, but it really
is a much safer way to wire them, and as John pointed out is required
by the 2008 NEC


Thanks to both of you for the explanations. I have another question
however:

If the gauge of the wire is appropriate for say 20 amps, and you
supply each wire designated for line from a separate 20A breaker, how
can the neutral wire be of adequate gauge for both circuits? In other
words, if 20 amps were drawn on each of the line wires and the common
neutral was used for both circuits, wouldn't the capacity of the neutral
be exceeded and be over 20 amps?? Maybe I am missing something?

The current wave cancels out. So if you have say 6 amps draw on 1 wire
and 7 amps on the other, then the combined current on the neutral would
be only 1 amp. 20A and 20A = 0A etc... So the most amps the neutral will
see is 20A.
Thats why it's important to keep the 2 wires on opposite hot legs in the
panel. Using a double breaker assures that.
If both hots are put on the same leg then the neutral will be overloaded.

Kevin