Michael Dobony wrote:
On Wed, 31 Dec 2008 06:54:34 -0500, John Grabowski wrote:

wrote in message
...
Hi!

I have a quick question and wondered if somebody can explain this to
me. While working on some wiring today, I got a bit of a jolt from
the neutral wire. When I tested it with my voltmeter, it read zero (I
had the breaker off). But then, when I grabbed the neutral, I got a
tingle.

I took my voltmeter and tested it, and it peaked up around 1 to 2
volts, then dropped back to zero. Did it again a few minutes later
and the same thing.

Upon further investigation, I found that there was one neutral that
was going to the furnace (on one circuit) and then up to the sockets
on the other circuit. One circuit (the furnace one) was live while
the other was dead.

Just so I understand, is the reason why I got a tingle was because
electricity was flowing through the live circuit? If I turned off the
circuit for the furnace along with the other one, would this have
prevented me from getting a little shock? I read one posting that
said to use the clamp to check for amps. Should I have done this
along with checking out how many volts are running through it?


*The neutral is a current carrying conductor. It sounds as if the one that
you are referring to is part of a multiwire circuit that is shared with the
furnace. When the furnace comes on there will be current flowing through
it. You should treat it like a live wire even when the circuit breaker is
off.

This is probably why the new electrical code does not allow sharing
neutrals between circuits.

The 2008 NEC makes no change to using common neutrals - they are still
allowed.

As several people have said, the 2008 NEC requires a common disconnect
which can be a handle tie.

AFCI circuits can't use a common neutral (unless the AFCI breaker is
240V). That is a limitation of the breaker, not the NEC. (AFCIs include
ground fault detection, typically at 30mA.) Because the 2008 NEC vastly
expands where AFCI protection is required in houses, the use of common
neutrals is effectively much limited.

The NEC applies to new wiring, not existing. (A jurisdiction can change
that.)

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