I was thinking about that yesterday, a couple of weeks ago I changed
some breakers from 1"'ers to the mini double style, and just moved the
(in-house) circuits. I am now planning on double checking it this weekend
to see if I need to move any of them. Just to be sure, am I correct in
assuming that I only have a problem if there is a shared neutral between
two hots, and that it should only occur when a 3 conductor + ground cable
is used? Or am I overlooking something?
Chris
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=> Not so. In this style of wiring, the neutral carries the difference in
=> load between the two hot phases, not the sum. (It's in the Canadian
=> Electrical Code to wire kitchens similarly to this - with "split
=> duplex" outlets, where the top outlet is fed by one phase and the
=> bottom by the other, but the neutral is shared.) There are a couple of
=> trick, most important being to wire the outlets so removing a single
=> outlet from service doesn't interrupt the neutral to the rest.
No requirement that the breakers even be side by side.
Someone making a change in the panel wiring could easily put both hots
on the same phase and now you do have a hazard. An innocent mistake
could start a fire.
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