Bill wrote:
On 12/7/2010 10:05 AM, Nova wrote:

The wiring arrangment using 12/3 for two feeds is called an "Edison
Circuit". Because the two circuits share a common neutral there is a
good chance that when one breaker trips the outlet/device affected can
still have a live neutral, being back fed through a device plugged into
the non-tripped circuit. This is the reason the two breakers should trip
together. I know my local code requires it and I think it's specified by
the NEC.

See:

http://www.phy.ornl.gov/divops/ESH/98-2.html


Then what's keeping all of the "live neutrals" from any of the other
circuits in the panel from raising their evil heads at any time? -- The
Ground (!), right? So, IF the former circuits are well-grounded, then
it seems the "Edison's Circuit" issue will not be a problem. Of
course, that's a crucial, "IF". Correct???

Regards,
Bill

The problem arises is you break the neutral path abck to the box when
servicing an outlet or device. The neutral may be hot even though the
breaker for that branch has been switched off.

--
Jack Novak
Buffalo, NY - USA