Electrical Wiring - Switch Hot Or Neutral?

[cabinetman]

There was a wiring diagram in Family Handyman recently showing some simple electrical issues around the house. They showed switch the Neutral. I don't know the specific reason why. That is the way I have always seen it drawn.

I've seen it advised that way too at times, but I've always switched the hot.
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[fbrend123]

If you look at any outlet, there is a silver terminal and a bronze terminal. The black wire (hot) always goes to the bronze terminal, and the white wire (neutral) always connects to the silver. If you look at an SPST switch, both terminals are bronze. So, logically, the black (hot) wire goes to both terminals of the switch. If you run a length of conduit from a ceiling light, you connect both the black and white wire in series with the black (hot) wire that supplies power to the light, and the other ends (both black and white) to the terminals on the switch. I believe that when you do that, code requires that you paint the white wire going to the switch black on both ends, to indicate that both sides are hot. Some electricians don't bother to do that, hence lots of confusion when someone looks at the circuit. That's my two cents' worth as a layman, and I won't even try to get into mutiple swictch circuits.

[woodturner]

Switch the hot - most of the time

NEC does specify that the hot be switched rather than the neutral, almost all the time.

The one exception is that in some configurations to wire three way switches, the white wire is used as the hot traveller. In this case, the white wire is switched - but to meet code, it must be taped or colored to be black, because it's really a hot, not a neutral.

I suspect that is the situation for the magazine article another poster referenced, but can't really say without seeing the diagram. The diagram could simply be in error - and wiring diagrams published in magazines are often incorrect, in my experience.

[os1kne]

I don't know anything about the magazine with the article in question, but I do think that it's a good idea to get multiple reputable sources of information / post a question here or similar forums to get the insight of experienced/knowledgeable people before proceeding with something you're not sure about.

Case in point: 2 or 3 years ago, I read an article in a WW magazine about using 12/3 romex to wire a typical home workshop with double gang outlet boxes. The idea was that each outlet box would have two 20A duplex receptacles, with each on a separate circuit. The article went on to say that an additional advantage of this is that you could replace the 120V outlets in a box for a 240V outlet basically anywhere for future tool needs (assuming only 1 240V tool would be used at a time). Seemed like a good idea.

While buying supplies for another project a couple of years ago, I found 250' of 12/3 on clearance due to an open package or something. Other projects with higher priorities came up, and I haven't yet got around to wiring the garage. I was starting to plan wiring the garage and posted about it a week or so ago because I was concerned that 2 GFCI circuits with a shared neutral may cause a problem. Anyway, I came to learn that what I was about to do (2-120V circuits with a shared neutral) was against current NEC code. Now I'll be using 12/2 for my 120V shop wiring, and I'm pretty sure that I have a lifetime (for my uses) supply of 12/3. So, it's a good idea to remember that the advice from a magazine article may not be good advice. (They can always print a correction in the following month that most people will never see.) Good luck!

[LCHIEN]

don't believe blindly everything you see on the internet!

[cabinetman]

don't believe blindly everything you see on the internet!

That's good advice. This was in a DIY magazine...anything wrong?
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[woodturner]

Anyway, I came to learn that what I was about to do (2-120V circuits with a shared neutral) was against current NEC code.

FWIW, current NEC discourages shared neutrals, but does not prohibit them.

[EDIT]: A shared neutral circuit is essentially a 240V circuit and MUST be wired to a two-pole breaker at the panel. It is not "legal" to wire it to two separate single-pole breakers.

I don't recommend the practice though.

You can still upgrade to 240 V later, though, if you wire each receptacle back to the panel. If you use 12-3, it's easy - just cap the red wire with a wire nut on both ends, connect the black and white for the 120 V usage. When you want to convert to 240 V, change the receptacle and use the black and red wires. Then change the wiring at the breaker to use the black and red on a double pole breaker.

[BobSch]

That's good advice. This was in a DIY magazine...anything wrong?
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Where to start...
2-wire cord (Lamp cord?!) has no ground. Use 3-wire cable and connect the ground.
Text says to connect to each side of outlet but pic shows both conductors to the same side.

Any more?

[master53yoda]

i'm not bitting wood turner but i'm the one that said it is against code I'm out driving nails with my hammer

[Tom Slick]

That's good advice. This was in a DIY magazine...anything wrong?
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I don't see anything right!

[crokett]

Where to start...
2-wire cord (Lamp cord?!) has no ground. Use 3-wire cable and connect the ground.
Text says to connect to each side of outlet but pic shows both conductors to the same side.

Any more?

It appears to be a metal box. The box should also be grounded.

[woodturner]

Please see edits to prior post #22

[mjernigan]

Jussi asked which tester I used...

I'm certain it's not the only one that might have kept me from losing my life as a result of loose standards, but its function DID spare me an early exit:

I use the Sperry HVH602, which I picked up either at HD or Lowes, can't remember which. Works great, gives a warbling tone when you place its plastic tip against a conductor or a conductor's insulation.

My only gripe is that it uses button cells rather than the more easily available AA or AAA, but given that at least once it saved my bacon, you won't hear me complaining loudly.

Mike

[crokett]

Fellas, it was a simple question, no need to quote code or anything. Oh and to make things even more confusing, I was out there late last night putting some tools away and I looked at it again. I think the way it was actually wired before I redid it was the white from the fixture came in to one switch pole. There was a white jumper from the other switch pole that was wired to black for the incoming hot. The black from the fixture was wired to the neutral.....

[mjernigan]

David--

True indeed, it was a simple question, but these things tend to grow when we get our hands on them. And regarding the color of the wiring: it's a convention, and while it certainly is good to wire according to convention, I don't think it's a safe assumption that someone actally did it the right way. I only avoided getting shocked because I stuck to my habit of always testing a circuit with the voltage sensor (and I test that each time, too).

I have pictures of my cut and bruised arm on my shop wall to remind me to keep the riving knife and anti-kickback pawls in place (and man! does kick-back happen in a hurry), because I didn't have a similar habit when I was cutting drawer bottoms a few weeks ago.

My caption: No shortcuts!

Maybe I'll learn.