3 way common? - Page 2 - Electrician Talk - Professional Electrical Contractors Forum

480sparky · 12-15-2008, 09:14 PM

Quote:

Originally Posted by nolabama

....what do you mean by dead end the three way?

A 3-way switch location with only a single 14-3 in the box..... no other NMs.

Kevin J · 12-15-2008, 09:15 PM

Quote:

Originally Posted by a-bulb

What is this? Run 2- 2 wires instead?

Naw, the ones I've run across, they use one 14-2 romex for the traveller. They then feed it on one end and switch on the other end. Here's the real kicker: you still have to have a feed in both ends so the switch leg can get its neutral. With 14-3, you acclomplish this with the white wire bringing the neutral over. What's really screwed up is that to do a two wire traveller "properly", you would need to run the same feed to both ends of the three way, but that's not how it usually happens. They normally steal the neutral they need from another circuit, which is usually closer than running the same feed around. Well, it works, until you service the three way. You kill the breaker that the three way is fed with, but what happens when the neutral gets a load on it from that other circuit that you got it from? Nice pleasent surprise.

nolabama · 12-15-2008, 09:41 PM

the wiring method kevin j describes will not allow a AFCI to function properly

Kevin J · 12-15-2008, 10:10 PM

Quote:

Originally Posted by nolabama

the wiring method kevin j describes will not allow a AFCI to function properly

I personally dont think it should be used anyway, 14-3 aint that expensive.

Bkessler · 12-15-2008, 10:57 PM

Quote:

Originally Posted by Kevin J

Naw, the ones I've run across, they use one 14-2 romex for the traveller. They then feed it on one end and switch on the other end. Here's the real kicker: you still have to have a feed in both ends so the switch leg can get its neutral. With 14-3, you acclomplish this with the white wire bringing the neutral over. What's really screwed up is that to do a two wire traveller "properly", you would need to run the same feed to both ends of the three way, but that's not how it usually happens. They normally steal the neutral they need from another circuit, which is usually closer than running the same feed around. Well, it works, until you service the three way. You kill the breaker that the three way is fed with, but what happens when the neutral gets a load on it from that other circuit that you got it from? Nice pleasent surprise.

If you have run into the situation you describe it is only because someone did not know what they were doing. I would not say "they", and" normally steel" , You may have run into this situation before but I would venture to say it's an isolated incident. And if an electrician does not understand what he is doing and making this mistake then that individual has no business working unsupervised and would make many, many other mistakes.