DIY Home Improvement Forum banner

adding new light, to existing switch

8K views 25 replies 8 participants last post by  stiksandstones 
#1 · (Edited)
Hello...
I am redoing my master shower, removed walls down to studs. While Im at it, I want to put a light/exaust fan unit in above shower. There is already a switch on the wall as you can see, that powers one set of lights in the bathroom. I simply want to tap into that switch to run this new shower light/fan.

I am going to imagine its a pretty simple procedure since I have access to everything, but just want to know from the experts-what to do?

(there are 3 wires coming out of the switch box, my guess is one is the MAIN power line coming in?, one going to the light its controlling, and the other seems to lead over to another switch down the room that powers another switch/light setup.....so would I tap into the current line that goes to the lights I want to run with for this shower light?......and there is a skinny white wire coming down, leads to nothing??)

Thanks

Craig
 

Attachments

See less See more
1
#3 ·
Yes, use this existing switch to still use its current light setup AND the new shower/fan/light.

Our bathroom has 2 recessed cans (on that switch) then a massive row of vanity's on another switch (will leave that vanity switch alone).

This current switch for the 2 recessed cans will work perfect also powering the shower light/fan.
 
#4 ·
easiest way is to run a cable from new light to other light controlled by the desired switch. Later you would tie new cable into the same wires as the old light. we would be glad to help if you need more direct info on which wires
 
#5 ·
that said we should probably ask some other questions, is the rating of the light/fan going to be too much for the circuit? we may need to have it GFI protected? is the fan rated to be install directly over the shower stall?
 
#6 ·
Cowboy, thanks for replying...

I have not purchased the light yet, so I will make sure its rated for shower use.

I am trying to get that electrical squared away so I can seal up that wall and get going on the shower work (laying the pan, hardieboard, WP membrane, etc...)


Can I do the preparation for the new light WITHOUT having the new light? I was assuming I could just splice in some romex wire to the wire LEAVING the switch that goes to that current existing light, tap into it, cap it off, wait till I am ready for new light?
 
#7 ·
Pending answers to the questions of Saturday Cowboy, I would run a wire from the existing fixture box to the location of the new light/fan. Don't hook it to anything. When you add the new light/fixture, hopefully, you can find the wire.

Understand that when you flip the single switch, all lights and fans will come on. If you think there is any chance you will change your mind, now is the time to add wires for additional switches. Once the walls are closed up, it is much harder.
 
#9 · (Edited)
Oberkc...

Good point, and I guess wouldn't be that hard to just add in an accompanying switch, so the 2 lights can be controlled separately...I mean, I want to add it on to a set that would go well for this area, but I guess would be nice to have ability to be separate.

And assuming I went that route, I knock out the SINGLE switch box, put in a new DOUBLE, wire it up, feed some new wire out for the NEW light that will get put it in later and good to go?


P.S. I didn't even think about the actual venting/duct needed for an exaust fan! ooops. Not even sure there is a route out for such a thing, have to investigate.
 
#12 ·
Only you can tell us if it is a good idea, as that comes down to personal preference. It can be done safely either way.

Yes it has to be vented either out the roof or out the wall.
 
#14 ·
Double switch? Do you mean that you would put a new double gang box where the curent box is or do you mean to put a single yoke double throw switch in? THe box you have in right now would not be big enough to add another cable into. Its not hard to take the old box out and replace with a bigger 2gang remodel box. I would vote for this so that you don't have the fan on every time you turn the can lights on. IMO
 
#15 ·
I'd consider a 3 gang switch box...one switch each for the lights and one for the fan. Gives you the most options for controlling the lights and fan, not to mention more room for wiring and timers. The 'skinny white wire' might be a phone line or t/stat wire....possibly used before...possibly for furture use...hard to say.
 
#16 ·
That skinny wire, looks like a lot of this alarm wire I see around attic, and in my master closet there is a whole end run of wires like that, maybe the main alarm control panel would go on this wall? Dunno, not interested in an alarm.

SO, onto my light project.
I bought this fan/light...it has the fan, light, night light:
http://broan.com/display/router.asp?ProductID=100236

Can I use this 3 button switch to control the unit? (night light, main fan light and fan)
http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053

I put a 2 gang box on the wall now...I could go back and put a 3 gang and put more switches, but would rather run it like this.

Thanks for the help.

Oh...and I ran 20amp romex wire up to that light, just one strand. Will I need more than that for this 3 switch deal?
 
#17 ·
The 3-rocker combination switch that you linked can be used for the light/fan/night light, where all 3 would be independently controlled. But now some issues need to be addressed...circuit ampacity and box fill.

What is the ampacity of this circuit? Meaning what's the amperage rating of the breaker you have to turn off to make this circuit dead? 15A or 20A? (This is to see what size wires you need to have in the circuit, which is going to effect box fill) While we're at it, what else is on this circuit?

You mentioned before that you started with a single gang box, now replaced with a 2 gang box, with 3 cables going into it. What size are those cables (14ga or 12ga) and how many wires in each? (I'm guessing just black, white & ground in each).

What the cubic inch capacity of the 2-gang box you put up?

I calculate needing 32 cubic inches minimum...(a 15A circuit) based on 4-14/2 NM (3 original cables and a new one to the fan/light), 1-14/3 NM (new to the fan/light) and 2 switch yokes. (Unless you can find some 14/4 to run to the fan/light...which would save you 2 cubic inches...but I wouldn't spend alot of time looking for it...it's not very common)

If this fan/light is going above the shower, it has to be GFCI protected (see instructions). What are your plans for that?
 
#21 ·
The instructions say nothing about GFI. So, is there an easy answer to "how do I do that?" ;)
As per the link you provided, page 1 of the installation instructions, items 7 & 8...

7. Acceptable for use over a tub or shower when connected to a GFCI (Ground Fault Circuit Interrupter) - protected branch circuit.

8. This unit must be grounded.
 
#19 ·
Ok, the breaker controls:
1-exterior flood light
2-6 bulb master bath vanitys
2-master bath recessed cans (that set is what was in that ONE gang box that I made a 2 gang)
1-master toilet recessed can
1-hallway recessed can entering the master bedroom
4-outlets, of which 2 in master bath that say GFCI on a decal, but no red/black switches, one in master closet on that run that does have the gfi switches on it.

I've attached pics of my inside wall since I have not sealed it yet for tile, pic of my breaker box and pic of the wall that has the one gang, now 2 gang box (only took a pic to show if I need to add a gfi outlet to this wall??)

The 4 wires: One is the 2 master recessed cans (the original ONE switch), I think one is the main line/current? and the 3rd was going out to the toilet room recessed can light. The 4th is the NEW romex I put in for my fan.





 
#20 · (Edited)
Box looks pretty full

Check with your local inspector regarding GFCI protection for your fan/light. When I installed a light above my shower, it had to have a waterproof cover. Can't speak for the fan! The Canadian code requires a minimum of 3 feet between a bathtub or shower to a light switch. The only gfci requirement I find in my code book (several years old) is for plug outlets or appliances such as whirlpool tubs.

If your fan/light may need GFCI protection then you should be able to tie in to the line downstream of your gfci plug outlet and run this to your new switch. But because this means running 2 more wires (14/2 with ground) into your 2 gang box, you may overfill it and need to get a bigger box or box extender. Your electrical supplier should be able to help you with sizing.

Regarding box filling. I am looking at an example for a 25 cu inch box. You would be allowed up to 10 wires and 5 marretts. The uninsulated (ground) wires are not included in the count.

Good luck

By the way, the electrical code allows a maximum of 11 outlets per circuit. You are at the max.
 
#22 ·
The pictures don't answer these questions....

What is the ampacity of this circuit?

What size are those cables (14ga or 12ga) and how many wires in each?

What the cubic inch capacity of the 2-gang box you put up? (should stamped inside it)
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top