3 in 1 switch wiring help

[turbo6justin]

Okay this is in a bathroom but you guys and gals rock so here we go.

I have a 3 in 1 switch (3 on off switches in one convenient little package) that I am using in my bathroom. One for the overhead fan, one for the overhead light, one for the shower light. Just for a disclaimer it is GFCI protected so no worries there.

What the heck kind of wire do I need to run up the wall into the attic? 14-3 14-4 14-5??? I will have hot/neutral/ground into the switch no problems yet. 1 hot to each light and fan, then I get confused. Can I run 1 common neutral to both fixtures shower light and light/fan combo (most likely with pigtails to each) and then the same with ground? Or would I be better off running the neutrals and grounds to a junction box and then off to the two repective fixtures? With this in mind I need 5 conductors right? In that case I would run 14-2 (partly because I have a bunch of it) and then two separate 14g wires to carry the other two hots. Sound good?

I am looking at the wiring diagram for the switch and just getting more confused and I am usually good with wiring diagrams. I can't figure out why they don't use the "com b" and what the whole 'splitting the circuit' thing is.

Please help.

And P.S. what can I expect in the soffit above the tub/shower, you know the standard drop ceiling over the shower thing. If I am thinking about it correct it should be uninsulated open space.

 

[MrMark]

I would run 3 12-2 or 3 14-2 NM up there. One cable for each switch leg is the easiest and cleanest way to do it. If it were only two items, say the fan and a light, you could run a 14-3 and have a common neutral return path.

 

[BigJohn20]

I'd do what MrMark said and run 3 x 12-2 NM-B. If you like having extra room to work with, consider replacing the current device box with either a deep box or 2 gang box with single device ring if possible.

If you want, you could run any combination of wires as long as you bring up 3 hots, 1 netural that can be pigtailed at a junction box properly installed in the attic, and an EGC. You could get away with a single 12-4/14-4 (3 Hots, 1 Neutral, 1 EGC) to a junction box and then run individual 12-2/14-2 to each outlet, but is it really worth the effort of going to a supply house to buy some x-4 wire?

Also, 12-4 is not the same as say a 12-2-2 even though they have the same number of CCC (Current Carrying Conductors). 12-2-2 is much easier to get around here, especially since we switched over to the NEC 2008 with the expenaded AFCI requirements. 12-2-2 around here will have a red, black, white, and white/gray with EGC, vs 12-4 being say red, black, blue, white, EGC.

 

[mrb]

you cant just run 2 more wires, nor can you run an additional cable to get one more wire. All the circuit conductors have to be in the same cable.

what else is in the box where the switch goes? Where is the GFCI protecting this?

 

[turbo6justin]

Well this is not going as well as I had hoped but I will answer some questions. I would run 3 14-2 or 1 14-2 and 1 14-3 and call it a day but there is no way I am going to fit 12 individual conductors into 1 box, 3 into the switch and 9 out. There is just no way even with a deep box. I was origionally going to use single switches but the wall they are going on would be door jam to corner solid with switches. 3 new ones 1 existing and an outlet, plus potentially a heated floor mat thermostat.

As for what is already in the box there is a single gang single switch and a single gang single outlet on that wall. The new switch would be next to the existing switch. I have three options for the GFCI protection, the last of which would be a new circuit from the basement, I am not woried about that part. I am a little confused why I can't use individual wires or why they all have to be in the same 'cable'. That would mean I would need a 5 conductor wire? If when I get out of the stud bay I run it the 5 feet or so through conduit would individual I believe called Thnn wire work? Or could I use 5 induvidual wires? I ask because there are other places in my house that have individual wires run (outside to a pool light and to a 3 season room for a hot tub sub pannel to name just two)

I think it is going to be tough to find anything but 14-2 or 14-3 wire in the box stores.

 

[mrb]

do you have a basement below or attic above this?

you can have individual conductors in conduit of course, but you cant just run some wires which is what it sounded like you were talking about. You also cant run an additional cable to get one more wire.

 

[mrb]

wait, you have loose individual wires to a hot tub subpanel? can we see some pics of that?

 

[turbo6justin]

I have an attic above. This is the first of two upper bathrooms I will be doing this to. Code didn't require bathroom vent fans in 1991 when my house was built as dumb as that sounds. As for the hot tub, no pictures but I think we are okay they are in a conduit from the braker pannel to the sub pannel. Actually I know they are okay because I disconnected them at the main pannel because I have no need for a hot tub at this point.

 

[mrb]

here's what I would do. Run some flex or smurf tube if allowed w/ 4 wires plus ground from the switch box up to a jbox in the attic (or use some 14-2-2 if you can get ahold of it). these wires will give power to the switch and return 3 switch legs. You will bring power into this jbox on a 14/2. The hot from this gets spliced to the hot to the switch. Run a 14/2 from the jbox to each of the 3 loads. The neutrals in these 3 cables get spliced to the neutral from the supply cable. The hots in these 3 cables get spliced to each of the 3 switch legs. Only 4 wires in the switch box and nothing hokey going on.

try to keep it on a 15a circuit and use #14 wire. i have broken a couple of these triple switches while cramming it into a box with #12 -its just too much force on the back of the switch...

 

[VHF]

I am a little confused why I can't use individual wires or why they all have to be in the same 'cable'.

An individual wire conducting current is surrounded by a electrical field and a magnetic field. The magnetic field can cause inductive heating of nearby metal objects, and the electrical field can cause radio interference.

Grouping the hot and neutral wires together means the electrical and magnetic fields (mostly) cancel out becaue opposite fields are produced by the current going out and the current returning.

This is reflected in code by the requirement that all conductors for a circuit are either in the same manufactured cable (i.e. NM/Romex) or are run in the same conduit. That's why you can't just add another wire--or even use two runs of 14-2/14/3--for the same circuit.

mrb's solution would minimize the number of conductors you would need to stuff into your switchbox.

...or you could replace your 3-in-1 switch with 3 separate switches for a total of 4 switches in a 4-gang box! Gives you plenty of room to work, and the ability to replace the fan switch with a timer if you desire.

 

[turbo6justin]

Great answer VHF, I started reading it and already knew the end. I never guessed for residential that the field interference would be a big concern. I guess I am kind of glad it is with all the wireless things we deal with now days.

Many thanks, especially mrb. I think I have two options. One is just as you describe it and the other is to use a 14-3 from the box for the fan/light combo and a 14-2 for the light only. I think I am going to give it a try to see if I can fit it al in. I have the cable to do either option. But I am glad to know I am covered.