Lighting/3-way

[stev'o]

This is now only my second post. I have been gathering a lot of great info from here.
Where I'm at, this is a pole barn, 54x36 with 12 foot walls. my electrical inspector has done his preliminary inspection. I have now wired all my boxes for lights and recepticles. The power company came today and put in the new service pole, and meter, and i have power. I went to the pole barn and checked my work. Here is what I think may be my problem, on my light circuit. I have two overhead florescent lights, outside lights over each entry door, and one over my overhead door. Plus a light directly over the inside of each door. These are one circuit. 15a, using 12 guage wire, given the length of runs. The power supply to the lights goes directly into one of the overhead florescent lights. I am switching these with three way switches, at each entry. At each entry, I have three switches for the lighting. I am powering each switch for the lights using the hot wire coming in from the lights. This is what I think may be the problem. Tomorrow, I will actually go out and check my wiring with my meter. I do not know if I should have a separte 12-2 wire coming into the switch box, instead of using the hot from the lights. The question is, can I use the 12-3 coming into the switch box, which is hot, to pig tail into the other switches? Or do I need to run a separate romex wire from the main panel, into the switch box?

Thanks.

 

[mrgm]

i like drawing things out then looking what i need

if you have a hot going to each switch, you should be good. if you have the power comming from the light, after, then that will not work

 

[stev'o]

From my panel, 12/2 to light-1. From light -1 to light-2, a 12/2 wire. Back to light-1, running from that box, to the two switch panels is a 12/3, with the white wires now hot. It is this white wire that I have pigtailed as hot, to the black wires of the other two switches in each switch box. I hope I have articulated this more clearly than my first post.

 

[BigJohn20]

You need to run from Light 1 to Box 1 with 12-2 (you only need to send power to the switches and then can pigtail to line side of each of the 3 switches), then from Box 1 to Box 2 with 3 x 12-2 (you need 6 conductors because each 3-way switch requires two conductors for the 2 travellers), then from Box 2 to the lights you want to energize. You'll use 1 x 12-2 for each bank of lights you are controlling.

Here's a crude MS Paint Diagram. Note: I left out the grounds to the switches and just used colors to indicated the NM-B that will send power to your light fixtures.

http://imgur.com/f5ivN

From what you describe, you're sending power from Light 1 to both Box 1 and Box 2, which you shouldn't be doing.

Depending on what revision of the NEC you're in and how the barn is finished and your wiring method, you may also need to bring the neutral into the 2nd box.

Also, you may want to do some reading on 3-way switches because it seems like you could use a better understanding of them.

There are also different ways to wire it, but I tried to make this as easy as possible to understand.