"Ben" wrote in message
ups.com...
I thought I was pretty good when it comes to wiring. I thought I knew
enough to be safe and have good quality work when I do it on my own.
Then I learned about shared neutral lines for different hot phases. I
am shocked I never heard of this. No book I ever read mentioned shared
neutrals for household wiring.
Given that a shared neutral is a possibility, I don't understand how
anybody can do electrical work without shutting off power to the
entire house. You can test for hot wires and verify at least one
circuit is off, but then somebody comes along and turns on a light and
suddenly the neutral is live. Not to mention the fact that if somebody
came along who didn't know about split neutrals who knows what they
may have mistakenly done in the past.

So what is the best way to proceed when trying to determine if a box
has any live wires or wires which could become charged if somebody
turns on a light upstream?
Are shared neutrals avoided where possible?
An electrician is about to rewire just about my entire house. Should I
request no shared neutrals or is this a silly request?
Thanks.

That is not really a concern; you can't get a shock off a neutral unless it
is unconnected at the breaker box and then you have much bigger problems.
They reduce voltage drop, save a little material, reduce congestion in the
breaker box and maybe save a little labor.
The big downside as I see it is that they can be confusing to people who
don't know what they are. My house had one with both hots on the same leg.
Didn't matter since not much was plugged into them, but it could have been a
disaster.
Also, I doubt you can use AFCI breakers, if that matters to you.