Split Neutral Wiring

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On Sun, 15 Apr 2007 02:40:31 GMT, snipped-for-privacy@milmac.com (Doug Miller) wrote:

I regularly install new switches and receptacles with the power on. I touch the black (hot) and white (neutral) wire regularly with the power on, just not at the same time. It is much faster and you don't have to reset any clocks.
If you are slightly cautious, there is absolutely no way you are going to get hurt.
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wrote:

There's a saying that there are old electricians, and there are bold electricians... but there are no old, bold electricians.

That's just foolish.

Make sure your life insurance is paid up.
--
Regards,
Doug Miller (alphageek at milmac dot com)
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Doug Miller wrote:

Hmm. There are hundreds of electricians touching live wires every day. With the proper precautions, it's not only safe, but required.
Think those who maintain the high-voltage distribution network.
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Of course -- but you're talking about professionals, who do that on a daily basis. *And* have had proper safety training, besides. This is a homeowner forum. Most of the posters here are *not* pros, and have not had the training and experience that the pros do.
Furthermore, I expect that the guys here who *are* pros would never advise a non-professional that it's safe to work "hot".
--
Regards,
Doug Miller (alphageek at milmac dot com)
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Very famous words.
Last words.
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I don't do it anymore, cause I really don't like the feeling when I do get shocked. BUT , when I was 13, my parents built on to the house. The electrician was a man my dad worked with. I personally landed some 40-45 duplex outlets and a dozen or more switches all with the power on. Like was said, stand on wood, touch one wire at a time and no problem. AND like I also said, I don't do it anymore.
There was another electrician where my dad worked (a large steel fab plant) who would probe voltages with one hand up to 440v. It all depends on the individual's personal resistance .
There was a hired hand on the farm he grew up on who would shut down the 4 cylinder tractor by putting his arm across all 4 bare spark plug terminals.
--
Steve Barker




"deke" < snipped-for-privacy@privacy.net> wrote in message
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I've never seen a neutral that wasn't tied together at the box and that was then tied to the earth ground.
Me thinks your wiring is screwed up.
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This is more of a "independent feeds into a single box" than a shared neutral issue per-se.
In a properly wired shared neutral circuit, getting zapped by the neutral can't happen - the neutral cannot be more than a volt or two away from ground.
If you disconnect the neutral, then someone fires up a lamp on the other side, yes, you can get zapped.
But:
1) Electrical code requires that neutrals on shared neutral circuits are pigtailed, so that it's possible to disconnect devices without breaking the neutral to downstreams.
2) There's a very strong hint that the neutral might be shared if you see 4 conductor wire (eg: 14/3 or 12/3 plus ground). Electrical code (at least ours) requires that, at least until the hots go off in different directions, that it's in a common cable. Since you can't parallel cable in normal residential wiring (eg: rejoin neutrals after splitting cable), at least theoretically, you'll always see /3 cable where the neutral is actually shared. Past the split point, it don't matter.
3) Because of (2), and electrical code requirements for common trip ("same strap" _requires_ common trip in the NEC, all shared neutrals in the CEC require common breaker trip), you'll almost always see a single cable connected to adjacent common-trip breakers You can't deenergize one hot without de-energizing the other.

Actually, until our (CEC) kitchen counter requirements changed a few years ago, at least two shared neutral circuits were mandatory in every house.

I wouldn't worry about it. Most of the concerns about neutral stupidities regarding what you've read is for industrial wiring botches, which is largely inapplicable to housing.
The electrician probably won't be tempted to use it much anyway.
What you _should_ do is insist that the electrician use tie-barred/common trip breakers everywhere he'd consider using common neutral (or two feeds into the same box - even a switch box), regardless of whether the NEC requires it for that specific instance.
The only times I've ever been zapped is where the electrician violated the CEC rule about having non-common-trip feeds into the same box. They weren't shared neutrals.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
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Shutting off power to the entire house is not a guarantee that the neutral won't be hot. Under rare circumstances if your neighbor lost his neutral connection it is possible that his return current would travel through the earth to your neutral connection and then back to the transformer.
You can test for hot wires and verify at least one

Always treat the wires as though they are hot. Every once in a while I get zapped by a neutral. Even though the ground and neutral are bonded together at the main you don't know what the condition of the neutral going back to the transformer is. You also don't know how good the neutral connections are at the panel. There is always the possibility of having a difference in potential between the ground and neutral at the load. In an old house it is a good idea to be extra cautious as you don't know what changes have been made over the years.

Some states are requiring arc fault circuit interupter circuit breakers for bedroom wiring. You cannot use a shared neutral on these circuits.

It is not a bad idea to discusss with him what his plans are. Afterall you are paying for it, you have a right to ask.
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On Fri, 13 Apr 2007 16:45:45 -0400, "John Grabowski"

Could you explain this a little more, really slow.
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wrote:

neutral
the
Coming off of the power company's transformer to a single family residence are two hot conductors and a neutral conductor.
The neutral conductor is the return path for the current to go back to the transformer from the two hot conductors.
The neutral conductor is bonded to earth via the water pipe and ground rods.
If you were to disconnect the neutral conductor the current will need to find another path back to the transformer.
It can go through the earth via the ground rods and water pipe directly to the transformer ground rod and grounding conductor.
However, depending on the location of the transformer and the neighbor's house (Or the quality of the transformer ground) the current might find a better path back to the transformer by going through the neighbor's water pipe and ground rods into the neighbor's electrical panel and then continuing through the neighbor's neutral conductor back to the transformer.
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I would think it would take the path back to the other winding in the transformer.
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wrote:

neutral
through
residence
the
rods.
to
a
water
transformer.
The primary? I thought that it is only the secondary that is grounded..
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On Fri, 13 Apr 2007 20:02:46 -0400, "John Grabowski"

I should have said other leg of the transformer. I am only talking about the secondary side.
Loosing the neutral on the secondary side will cause 240V across any connected loads.
I can't see taking a neutral path to your neighbor's house.
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wrote:

to
ground
to
directly
neighbor's
find
The only circuits that will be affected by that are the ones that share a neutral. Loads are not always perfectly balanced so the neutral will most likely always have current going to it.

I figured. End of discussion.
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I'd put that a different way. Shared neutrals are incompatible with single pole GFIs. They aren't incompatible with double-pole GFIs, and single GFIs can be used _after_ you split the neutral.
Shared neutral double pole GFIs would be code here for kitchen counters, except that they're so bloody expensive. Shared neutral non-GFI _were_ code, but not anymore.
We've adopted a modified version of the NEC for kitchen counter outlets. You can still use shared neutral, IF you're willing to pay for the dual GFIs, but otherwise, you use 20A singles.

I have 5 split neutral circuits in my shop ;-)
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
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