# Bathroom light/exhaust fan/heater wiring



## rselectric1 (Oct 12, 2009)

If the old unit only had 2 wires (switch leg and neutral) running to it then all three functions had to be either all off, or all on at the same time. Is that how it operated before?

There is no problem with wiring the fan and light portion to turn on together, but you will want that extra switch leg to let the heater run only when you want it.


----------



## Redlos (Oct 18, 2009)

That's the weird thing, the old unit as was ble to operate the light, fan, heater independently using each switch. Even though is only had two 12/2 wires running to it....I want to keep that functionality. Which was why I was planning on running a 12/3 wire...but since I'm struggling I thought I'd rewire the way it was before. So it begs the question, how the heck was it working before?


----------



## rselectric1 (Oct 12, 2009)

Inside the electrical box attached to the old unit, how many wires were entering? Only 2 plus ground? And what switches controlled the other functions?


----------



## rselectric1 (Oct 12, 2009)

Redlos you still there?
This is intriguing. The only thing I can think of is that there is another cable running to that unit that you just haven't discovered yet. It should all become obvious when you trace the switches that were running the other operations.


----------



## Redlos (Oct 18, 2009)

Sorry, had to take care of the 4 yr old. No I'm 100% positive there were only two 12/2 wires running to the original unit. I have another heater/fan/light in the master bath, but can't get access to it (vaulted ceiling). I'll try to post pics of the older switch and unit, I seem to recall a lot of legs tied together inside the unit, is there any way it could have been controlled by the neutrals? Sorry but while I', overly handy, home electricity is not my strongsuit


----------



## rselectric1 (Oct 12, 2009)

I hope they were not being controlled by the neutrals-that's dangerous.

Were the switches that controlled the various functions typical looking switches that were separated or were they part of a control where they were all connected together?

Yeah pics would help.


----------



## Redlos (Oct 18, 2009)

About to post some pics


----------



## Redlos (Oct 18, 2009)

Added photos to the Photos Section, trying to figure out how to post in thread...sorry, first time to site


----------



## Redlos (Oct 18, 2009)

Pics of switch


----------



## Redlos (Oct 18, 2009)

So if the "safe" wiring is to use a 12/2 & 12/3, I'll figure out a way to get the new wire thru the ceiling and wall and run as the Broan diagram shows. I was just stumped as to how it worked before...adm I also assume the other fan is wired the exact same way. If it's really unsafe, I'll have to address. Granted it's likely been operating as is for the past 15 years or so....


----------



## Redlos (Oct 18, 2009)

bump...


----------



## rselectric1 (Oct 12, 2009)

OK that's a start. Those black wires on the back appear to provide power from 1 individual switch to another. But I still think that inside the box that this switch came from, there should be 3 individual switch legs that all run up to the fan unit. Please post a pic of the inside of the box that switch came out of.


----------



## rselectric1 (Oct 12, 2009)

Redlos said:


> So if the "safe" wiring is to use a 12/2 & 12/3, I'll figure out a way to get the new wire thru the ceiling and wall and run as the Broan diagram shows. I was just stumped as to how it worked before...adm I also assume the other fan is wired the exact same way. If it's really unsafe, I'll have to address. Granted it's likely been operating as is for the past 15 years or so....


My thinking is that there is already another cable running to the box that you just haven't noticed. The end of which will be the extra switch legs in the box the switch came from. (probably just out of site and laying near the fan location)


----------



## CookeCarpentry (Oct 17, 2009)

Redlos - you should consult an electrician.

Anyone besides rs....


----------



## Redlos (Oct 18, 2009)

Sorry for the poor quality, camera is dead and have to use iPhone. The wires with the nuts are the hot leads from sub-panel, other 2 12/2 wires run to fan/light/heater...does this shed any light?


----------



## rselectric1 (Oct 12, 2009)

CookeCarpentry said:


> Redlos - you should consult an electrician.
> 
> Anyone besides rs....


Huh? Joking?


----------



## CookeCarpentry (Oct 17, 2009)

rselectric1 said:


> Huh? Joking?


Kidding. :thumbup:


----------



## rselectric1 (Oct 12, 2009)

OK-it's becoming clearer now. 

It looks like you do indeed have several switch legs. I am assuming that the wires from the top of the box go directly to the fan unit. If this is the case, then there is a cable that you disconnected when taking out the old unit laying up in the ceiling somewhere. You already have the wiring you need. Most likely another 12-2. The electrician used 1 of the white wires as a switch leg, but forgot to re-identify it. (This is done by wrapping a small piece of black electrical tape around the wires)

If the above is true, you are fine. Please look for that extra cable-it has to be there hiding in the insulation somewhere.


----------



## Redlos (Oct 18, 2009)

2 of the wires run to the fan, the other runs the opposite direction (away from subpanel) but I assumed it was the source (load) line.


----------



## williswires (Jul 21, 2008)

What you probably had was two 12/2 cables (2 blacks, 2 whites) going up to your fan/light/heater and wired this way:


Black (HOT-SUPPLY) from supply connected to 1st switch. The jumped to the other 2 switches to provide power for those switches.

White (NEUTRAL-SUPPLY) connected to one of the whites going to the fixture to supply the fixture (fan/light/heater) with the required neutral.

Switch 1 = one black goes up to fixture for fan HOT
Switch 2 = one white goes up to fixture for light HOT (should have been reidentified as a hot using a black marker, tape, etc on both ends)
Switch 3 = second black goes up to fixture for heater HOT

This is an example only. Where they exactly went depends on what you found when you disconnected the old fixture.


What is the model of your new fixture? Does it have a 2-speed fan (this would require an additional wire that your old one didn't have)?


----------



## rselectric1 (Oct 12, 2009)

Redlos said:


> 2 of the wires run to the fan, the other runs the opposite direction (away from subpanel) but I assumed it was the source (load) line.


You're getting closer-find that other cable and it will all make sense.:thumbsup:


----------



## Redlos (Oct 18, 2009)

OK, looksl ike you'll need to educate me a little. All I see in the box right now is three 12/2 wires (3 black, 3 white, 3 bare grounds), two of the ground wires are currently connected together. I thought one wire brought in the current and the other two run back to the fan.

In the attic @ the fan location there are only two 12/2 wires...sorry for being so ignorant and I truly appreciate your knowledge/assistance


----------



## Redlos (Oct 18, 2009)

The new fan is Broan 100HL, single speed fan.


----------



## Redlos (Oct 18, 2009)

williswires said:


> What you probably had was two 12/2 cables (2 blacks, 2 whites) going up to your fan/light/heater and wired this way:
> 
> 
> Black (HOT-SUPPLY) from supply connected to 1st switch. The jumped to the other 2 switches to provide power for those switches.
> ...


 
Would this have left all the whites connected together in the unit in the attic?


----------



## williswires (Jul 21, 2008)

Redlos said:


> Would this have left all the whites connected together in the unit in the attic?


All except the one being used as a hot. Do you recall what your attic junction box connections were like?


----------



## rselectric1 (Oct 12, 2009)

Dont get ground mixed up with neutral. They are different.
From the photo you provided, it appears that the 2 black and 1 white wire (the ones that are straight and not bent) are your three switch legs. The white wire that has the curly-cue on it appears to have been attached by wire nut and is probably your neutral feed to the fan unit.

If you have a voltage tester, turn the circuit back on and isolate the two that give you 120 volts. Those are your supply conductors. I think they will be the ones coming from the bottom opening of the switch box.


----------



## Redlos (Oct 18, 2009)

Williswires: there isn't a junction box. The original 12/2 wires fed into the unit but I remember when I looked inside there were a ton of whites all tied together. Currently there isn't a junction box in the attic. Just the two 12/2 wires leading from the unit location into the wall and another 12/2 going into the wall also.

RS1: I've only been able to find 120V on one 12/2 wire, the pair that now have the wire nuts, the other two 12/2 go to the unit location.


----------



## Redlos (Oct 18, 2009)

Just to make a point, all I'm looking to do is get the new Broan 100HL working with the existing two 12/2 wires (as long as it's SAFE)...or be 100% that I need to run a new single wire or 12/3 wire and hook it up as the instructions show...thx again.


----------



## rselectric1 (Oct 12, 2009)

Eureka-I just read back to post #23. You do indeed have an extra cable up there for a total of 4 conductors plus ground. (That's all you need!)

Follow willis's post. He layed it out better than I did. We are all on the same page here.

Mystery solved.


----------



## rselectric1 (Oct 12, 2009)

All is well and you don't have to run any extra wires. If you're ready I'll tell you how to hook it up.
You will need a voltage tester to do this.


----------



## Redlos (Oct 18, 2009)

Thanks so muc, I'll digest this and follow WIllie's post (#21). Thanks sooo much for your time/efforts, gotta go take care of the kid.


----------



## Redlos (Oct 18, 2009)

RS1, please tell me yes, I have a voltage tester...or you can email me @ 

[email protected]. Thanks gotta run for the night, will tackle next weekend!!:thumbsup:


----------



## williswires (Jul 21, 2008)

The Broan 100HL diagram shows one 20A supply circuit is required for this fixture rated at 14A. The supply circuit goes to the switches, and has one 12-2 cable going to power the heater, and a 12-3 to power the light & fan.

But I see no reason why they specified to have 2 neutrals going up to the fixture, unless I'm missing something in the code or UL listing requirements that would require the heater to have it's own neutral. But since the installation instructions have it that way, you should try to do it that way.


----------



## Redlos (Oct 18, 2009)

So then I DO need to run another wire for this installation? :huh:

This is why I'm confused.....if I follow the instructions I have to run a new wire...I was trying to see if there was a legitimate and safe workaround...thought?


----------



## rselectric1 (Oct 12, 2009)

No-I just analyzed the specs that Willis posted. The other neutral is probably shown for simplicity. I agree with Willis. One of the neutrals can be used as a switch leg as long as it is re-identified correctly. Don't over analyze the specs, all you need to do is hook this thing up EXACTLY as it was connected before.

If you are really ready to take some step by step instructions, I can give you a little more time tonight and can talk you through this. Since I have some time invested in your project, I would love to see it resolved too.


----------



## Redlos (Oct 18, 2009)

SO I would just need to wire according to the diagram, but swap the white neutral wire going to the heater and attach it to the blue wire of the light/fan? Basically disregard the "extra" neutral going from the switch to the heater and use it as the "red" wire (extra wire I don't have) from the "light" switch to the "blue" wire at the unit? Connect both neutral (white) wires @ the unit to one white coming from switch.

Please let me know if this is correct...also what's the easiest method of figuring out which wires are which from the box (wall switch) to the attic? I was thinking I could attach a pair of wires at the switch to the load wires then use a volt meter to see which are hot? Is there an easier way?


----------



## williswires (Jul 21, 2008)

The mfg probably shows it having two cables to be inaccordance with NEC 300.3(B) which says conductors of the same circuit must be in the same conduit, cable, etc. 

This means that using one of the 12-2 to run two hots doesn't conform to the code because the neutral of those two hots is technically in another cable. That's why they show two cables, so each cable has the neutral for the hots that are in that cable.

*(B) Conductors of the Same Circuit. ​*​​​​All conductors of
the same circuit and, where used, the grounded conductor
and all equipment grounding conductors and bonding conductors
shall be contained within the same raceway, auxiliary
gutter, cable tray, cablebus assembly, trench, *cable*, or
cord, unless otherwise permitted in accordance with​
300.3(B)(1) through (B)(4).


----------



## Redlos (Oct 18, 2009)

So if I give up on running the extra wire and use only one shared neutral wire, I'll be out of code.....is this "unsafe" or in any way hazardous? or just out of code?


----------



## Redlos (Oct 18, 2009)

*It WORKED! Job completed*

Thanks so much for your help guys. Since we got some cooler weather in Baton Rouge, I took the opportunity to get back in the attic. The wiring worked perfectly, shared the neutral and used the unused white wire as my "extra" leg. I truly appreciate your efforts to help me out, take care!!:thumbup:


----------

