July issue JLC, 3-way switching

[edlee120]

Anyone see the question and answer in this month's JLC?

http://www.jlconline.com/cgi-local/v...177f00000105ca


Take a look at the drawing: white conductor marked with black tape and used as the switch leg. Jeesh.

Someone should write a letter.

Or maybe just bitch about it here :-)


Ed

[littlebluetruck]

Re: July issue JLC, 3-way switching

It seems this is commonly done, and for my part I see no problem with it.

What is your alternative? Do you use 14/3 so you have black and red?

[jwelectric]

Re: July issue JLC, 3-way switching

It seems this is commonly done, and for my part I see no problem with it.

What is your alternative? Do you use 14/3 so you have black and red?

200.7(C)(2) Where a cable assembly contains an insulated conductor for single-pole, 3-way or 4-way switch loops and the conductor with white or gray insulation or a marking of three continuous white stripes is used for the supply to the switch but not as a return conductor from the switch to the switched outlet. In these applications, the conductor with white or gray insulation or with three continuous white stripes shall be permanently reidentified to indicate its use by painting or other effective means at its terminations and at each location where the conductor is visible and accessible.

As a code enforcement official this would get turned down as a violation of the above section of the NEC.

The article is what I have always heard as "the blind leading the blind"

This is a classic case of someone seeing something work and not seeing the danger involved.
This is also why it takes years of training to become an "Electrician" instead of an installer.

[littlebluetruck]

Re: July issue JLC, 3-way switching

I've been straightened out (see below)

[edlee120]

Re: July issue JLC, 3-way switching

It seems this is commonly done, and for my part I see no problem with it.

What is your alternative? Do you use 14/3 so you have black and red?

It may seem picky to a non-electrician, but the white taped wire is supposed to be hot ALL the time.........not used as a switch leg. This is to prevent confusion when the light is turned off: the white wire would not be hot, so someone might assume that it is a neutral or generally be confused. Or what if the person installing it doesn't bother to mark the wire? Then you have two white wires feeding a fixture. So the code reasonably requires that the re-marked white ALWAYS be hot and the switch leg will be the factory black or red conductor.

If you look at the picture, the "far" 3-way switch with the white on the common, this terminal could be energized or not depending on the position of the switches. This is bad.

All they have to do in the aforementioned diagram is rearrange the connections and it could be correct (as long as tape is considered "permanent" by the AHJ, which is another matter).


"The article is what I have always heard as "the blind leading the blind"

The answer in the magazine was provided by a master electrician, though I don't suppose he drew the diagram.


Ed

[littlebluetruck]

Re: July issue JLC, 3-way switching

Thanks Ed - that makes sense. I thought you were objecting to using the as a current carrying conductor at all. I didn't catch the distinction. We're good now.

[edlee120]

Re: July issue JLC, 3-way switching

Great. I was editing while you were posting, didn't mean to beat a dead horse.

So you wanna write the letter?


Ed

[George Stolz]

Re: July issue JLC, 3-way switching

If you look at the picture, the "far" 3-way switch with the white on the common, this terminal could be energized or not depending on the position of the switches. This is bad.

I disagree with that aspect being a code violation.

The cable between the switch and the light was misused, but the three-wire cables between the switches can be in any arrangement, IMO. In fact, it's in line with a diagram from the '99 Handbook, if I recall correctly. That diagram has been used to state that the conductor from the first switch to the second's common has to be white, but I disagree with that as well.

The first switch, "A", has no single supply; therefore, 200.7(C)(2) can't be applied logically to the travellers/common, IMO. It can always be applied to the cable between the light and the switch, however, and I believe that to be the intent of the section.

My two cents. :)

[jwelectric]

Re: July issue JLC, 3-way switching

Yea, what George said!

I agree with you completely George. I had the good fortune to sit through about 2 hours of hearing this debated about three years ago.
The consensus was as long as the white was not used to return to the light everything was okay.

The illustration used in the article shows the white being used to return to the light which is a violation of the NEC.

[frenchie]

Re: July issue JLC, 3-way switching

So you wanna write the letter?


Ed

I just sent them an email with a link to this thread. You all should, too - it's easy enough, just hit "contact us" at the bottom of the page, one of the auto adresses is the editorial board.

BTW, if anybody's got a good idea for an article, I know for a fact that they're always looking for contributors...

[sparkyinak]

Re: July issue JLC, 3-way switching

Mike,

I guess this makes me a dumb installer. Although I do not wire my switches in the same manner per the drawing, why is it a safety concern outside that the NEC says you can not do that? I am currently on the road so I do not have access to my library of nerd books and I am too nerdy to wait to get home to look it up. You got my cariousity on it now. Only thing I could see being a safety issue is someone assumes that the marked wire is not the returning wire. anytime I deal with switch legs and travelers, I identify what is what first before connecting anything. There is too much riding on it to assume and get it wrong.

[jwelectric]

Re: July issue JLC, 3-way switching

See post 5 for a good explaination

[johnny watt]

Re: July issue JLC, 3-way switching

Sometimes the code is just ridiculous.
This is one of those times.

[jwelectric]

Re: July issue JLC, 3-way switching

Sometimes the code is just ridiculous.
This is one of those times.

No matter how ridiculous I find it in every code cycle all the way back to 1962.

It has to do with reversing polarity of the fixture and is a life safety issue. Just because you know what you are doing does not mean that someone else knows what you are doing. The are rules are set in place for the safety of everyone not just one.

[edlee120]

Re: July issue JLC, 3-way switching

Sometimes the code is just ridiculous.
This is one of those times.

Not if you've ever been struggling to make wiring repairs in a dark, crowded location (like a commercial basement, an industrial location, whatever) where there are a bunch of different switches and lights, the wiring is old, the boxes stuffed and you can't turn circuits off because of some reason or other relating to the functioning business, unlabelled panels, long distances/locked doors from one area to the next, etc. etc.

A switched white wire is just one more fly in the ointment to make it more problematic, confusing and possibly unsafe.

We don't always get to work in brightly lit, clean environments with correctly labelled panels, boxes filled to code, happy owners who gladly let us turn circuits off while we work, existing newish wire with obvious color coding and undamaged insulation.

Thank you for your comment :-)


Ed