Electrical- Securing live wires between removal and installation (2 weeks)

[docrowan]

Depending on how things are wired it doesn't matter if the switch breaks the neutral or hot. If the power comes into the switch box, then switching the hot is safer. If power comes into the light fixture box, then whether or not the switch is off, there is still power at the light. Personally, if I am ever sticking pliers into a light socket I am turning the breaker off first.

In my experience, power always comes into the light fixture box, and flows from there to the switch box.

I, too, cut the breaker AND I always use my go/nogo tester before I touch anything electrical. Fixing a neutral switch protects the uninitiated, not the knowledgeable handyman or professional.

[chopnhack]

masteryoda - what raised the floating bridge? Was this a drawbridge where the mechanism failed and the bridge raised up or....?

In the field working I have seen many neutral switched lights and on a commercial control system that I was involved in investigating a switched neutral went to ground and raised the I-90 floating bridge in Seattle and killed a couple that hit the rising bridge at 60 miles per hour. Never ever switch a neutral, the results can be deadly.[/QUOTE]

[crokett]

The NEC also requires all electrical receptacles in the bathroom be run through a GFI circuit which monitors the current flow between the hot line and the neutral line and if they are not the same will break the circuit in 120th of a second..

I'm not advocating switching the neutral. I'm just saying if power comes in at the light fixture, it doesn't matter whether the neutral is switched or not, there is always power at the fixture on one side of it and the safest thing to do is cut off the breaker if you are sticking things into light sockets.

[master53yoda]

it doesn't matter whether the neutral is switched or not, there is always power at the fixture on one side

When the line comes into the box the white wires (neutral) are connected and the black wire (power) goes to the switch and then to the light, with the switch off there is no power at the fixture. The neutral is common with the ground in the panel the neutral has no energy connected to it in relation to the ground.

If the Neutral is switched there is power at the fixture in relation to the grounded faucets with the switch off.

[master53yoda]

masteryoda - what raised the floating bridge? Was this a drawbridge where the mechanism failed and the bridge raised up or....?

In the field working I have seen many neutral switched lights and on a commercial control system that I was involved in investigating a switched neutral went to ground and raised the I-90 floating bridge in Seattle and killed a couple that hit the rising bridge at 60 miles per hour. Never ever switch a neutral, the results can be deadly.

[/QUOTE]

The bridge was raised because the neutral was switched and when the switch line was shorted to ground it turned on the hoist mechanism raising the bridge. The short was a bur on one conduit and cut through the insulation on the wire. If the power line would have been switched correctly the short would have blown a fuse instead of turning on the hoist mechanism.

[crokett]

When the line comes into the box the white wires (neutral) are connected and the black wire (power) goes to the switch and then to the light, with the switch off there is no power at the fixture. The neutral is common with the ground in the panel the neutral has no energy connected to it in relation to the ground.

If the Neutral is switched there is power at the fixture in relation to the grounded faucets with the switch off.

It depends on how you wire it. In my house I've replaced the fixture in 3 bedrooms, the living room, hall and new bath. Of those, 5 had power coming to the fixture and all had power in through the fixture to the switch and the neutrals were tied together in the fixture box. I've no idea if that was code 30 years ago or not but it is the way it was done.

[LarryG]

David, the power may come to the fixture before it goes to the switch -- that's done all the time -- but if the switch breaks the circuit there is still no power at the fixture. If it were any other way, the light would burn all the time and the switch would have no effect.

[RAFlorida]

Switching the neutral will get you in big trouble.

The NEC states it very clearly. I've never been able to understand why any one would switch the neutral to begin with. Don't tell some one to do something that is against the NEC code. The code goes back into the 50s about never switching the neutral.
To help clearify: Most times a single romex is brought down from the light and to the switch for control. Many times the electrician will run the black to the top screw of the switch and the "white" to the bottom screw. That's correct except for the color of the neutral, by NEC code, the white wire now must be black taped, painted black, red, etc. or otherwise kill the id of the neutral.

[Hellrazor]

The NEC states it very clearly. I've never been able to understand why any one would switch the neutral to begin with. Don't tell some one to do something that is against the NEC code. The code goes back into the 50s about never switching the neutral.
To help clearify: Most times a single romex is brought down from the light and to the switch for control. Many times the electrician will run the black to the top screw of the switch and the "white" to the bottom screw. That's correct except for the color of the neutral, by NEC code, the white wire now must be black taped, painted black, red, etc. or otherwise kill the id of the neutral.

That is correct. Black tape is the best way. I saw a show on one of the DY channels the other day and the "electrician" was using a black marker on the neutral wire. I wouldn't trust that to be permanent by any means.

[docrowan]

David, the power may come to the fixture before it goes to the switch -- that's done all the time -- but if the switch breaks the circuit there is still no power at the fixture. If it were any other way, the light would burn all the time and the switch would have no effect.

Larry,

This is not correct - you can run the neutral leg to the switch and the fixture will appear to turn on and off properly. The danger is the light fixture always has power to it, it just has nowhere to go. So it's sitting there waiting for something or SOMEONE to connect it to ground.

On the other hand running the hot leg to the switch means the fixture has no power to it when the switch is off.

My wife's uncle removed a chandelier when we were moving her grandmother into a new house. He simply turned the power off at the switch and removed the fixture. He was lucky, as it turned out it was wired to a three way switch but nobody flipped the other switch while he was working on it. I came along behind him to reinstall the chandelier and found out about the three way switch with a few sparks. Had it been a neutral leg switch he would have gotten at least a little jolt.

[LarryG]

On the other hand running the hot leg to the switch means the fixture has no power to it when the switch is off.

That's what I meant -- I was assuming a properly wired switch, NOT a switched neutral. Admittedly, I was not clear on this critcal point.

[docrowan]

I understand now. As you can tell, I'm kind of passionate on this subject. I'm no longer a cussing man, but I definitely don't have kind thoughts toward my previous homeowners. They've left a lot of things for me to clean up where just a little more effort on their part would have brought them up to code and I wouldn't have to fool with them.