On Sep 17, 8:44 am, "
wrote:
On Sep 17, 9:33 am, Andy wrote:



On Sep 16, 6:29 pm, Doug Miller
wrote:

On 9/16/2011 6:43 PM, Andy wrote:

On Sep 16, 6:15 am, Doug
wrote:

Also, someone working on one circuit and not knowing that the neutral
carries current from a different circuit could receive a fatal shock
from that neutral -- how would he know to shut down both circuits?

Andy comments:
I am confused as to how you think someone could receive a shock
from the "neutral" wire...

Because it carries current. The same current that's in the hot.

It is normally not disconnected in any
configuration ---

It doesn't really matter whether it's disconnected or not. It's carrying
current.

Consider two simple circuits, A and B, each supplying no loads other
than a single 100W light bulb, each of which is turned on -- but,
unbeknowst to you, their neutrals are cross-connected. Well and good.
Now suppose you need to replace the fixture on circuit A. Knowing that
it's on circuit A, you shut off that breaker, and disconnect the hot
lead to the fixture. Now when you go to disconnect the neutral lead, you
get a shock, because -- and I think this is the point you are missing --
electricity doesn't "follow the path of least resistance" as many people
believe, it follows *all possible paths*, including the one that you've
just made with your body by touching that energized lead.

Andy comments:

You are incorrect. I suggest you actually try it. Both neutrals
are
connected together, HARDWIRED, at the sub panel... You are no
more likely to get a shock from one as from the other...

But, I'm not here to argue with you... My input is to Ivan... He
is
smart enough to read all the inputs and decide for himself...

Andy in Eureka, Texas, Licensed Electrical
Engineer....- Hide quoted text -

- Show quoted text -

They are in fact wired together and I see your reasoning.
Now consider this. The hardwired together theory works if
there is no resistance in the netural wires all the way
back to the panel. In the real word there is some resistance
in the neutral wire of the second energized circuit along
the way. Resistance of the wire, any connection points,
eg wire nuts, etc. Now if the second circuit is energized
and carrying 15 amps, there will in fact be some small
voltage potential there relative to ground. So, it's not
the same as the neutral for the disconnected circuit.
It's not likely to be enough to shock you, but that is
provided EVERYTHING ELSE IS WIRED AND WORKING
PROPERLY ON THE OTHER CIRCUIT.

And leaving that neutral there opens up the possibility
that someone else will come along someday, see
it, and decide to tap on to that circuit for something
else, eg new outlets, loads, etc. Now you have
a conductor inadequate for the overload protection.
It also screws up GFCI protection, whether now or
in the future.

I'm surprised that an EE woudl in essence give
an OK to what most of us consider a serious
code violation.

Andy comments:

I can surprise you as much as you like...

I agree with your hypothetical situation.... Ivan is aware of it
now, and can make up his own mind about the risk....

Why not confine your advice to Ivan, rather than trying to
do a "'one-upsmanship" jihad on other posters , although
it seems to be a "natural" for you ... ??????

Andy in Eureka, Texas