Bathroom Light => Light/Fan/Heater Combo

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  #1  
Old 06-24-06, 05:05 PM
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Bathroom Light => Light/Fan/Heater Combo

Afternoon,

I'm wondering if anyone can guide me through the wiring connections I would need to run to replace an old bathroom light with a light/fan/heater combo.

The current box has power coming down from the attic and into the box. A wire leaves the box and goes back into the attic to the current fixture. A third wire leaves the bottom of the box, powering the next item on the circuit.

All cables have white/black/ground.

In the box currently, all 3 whites are wirenutted together.

3 blacks are wire nutted together.
Ceiling wire 1 goes directly to the switch.
A little wire goes from the switch to the wirenut.
Ceiling wire 2 goes to the wirenut.
Floor wire comes from the wirenut.

One comes from the ceiling, directly to the switch, one small piece from the switch to the nut, and another from the nut down and out of the box.

I've yet to purchase the fan (no wiring diagram to follow).

Do i need to run a new 2wire+ground cable for each function? (2 new cables wires for the fan/heater?) Can I run some kind of 4 wire + ground (white/blue/red/black?) cable?
 
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  #2  
Old 06-24-06, 05:39 PM
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You probably need a new circuit. A heater takes quite a bit of current, and a typical shared lighting circuit cannot handle it.

If there were enough power on this circuit, then you would need to replace the cable from the switch to the existing light.

Depending on what you wanted to be able to control separately, you would need to go to three conductor cable (plus ground) to have the light and fan on together and the heater separate, or four conductor cable (plus ground) to have all three devices controlled separately.

However, I say this again. You likely do not have enough capacity on this existing circuit for a heater. What are the specifications of the device, and what size is the circuit, and what else in also on this circuit?
 
  #3  
Old 06-24-06, 06:48 PM
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The circuit is 20a.
I didn't build the house, but from testing everything in the area i can find, I >think< includes this bathroom light, then the outlet above the bathroom vanity, and then through an adjoining wall into 2 outlets in the master bedroom.

Looking at this fan from Home Depot:
http://www.nutone.com/product-detail...roductID=10154
"Fast-warming 1500W fan-forced heat, 70 CFM exhaust fan and bright 100W ceiling light" it later mentions the heating element is 'nickel-chrome' if that makes a difference.

IWe do want each of the functions (heat, fan, light) on a separate switch. Is it possible to run three pieces of cable (b/w/ground) instead? We have a spool of leftovers from an earlier project.
 
  #4  
Old 06-24-06, 10:14 PM
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You should already know what is on the same circuit as the existing light. You should know what is on ALL the circuits in your house.

The installation instructions clearly state that the unit requires a dedicated circuit. You need to run a new circuit from the main panel for this unit. While you are at it, I recommend you run a circuit for the bathroom receptacle.


Even if the instructions did not require a dedicated circuit, you would not want this on the same circuit as any other loads. It simply draws too much current.

And, to answer your last question. No, you probably cannot run a separate piece of two wire cable for each of the three functions of the unit. Box fill at the switch could be an issue, and the unit probably has only a single neutral.
 

Last edited by racraft; 06-25-06 at 05:38 AM.
  #5  
Old 06-25-06, 05:12 AM
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I just bought a similar unit and it uses 13 amps and requires a dedicated 20 amp circuit. I'll probably put the heater on a 15 min timer switch, so it can't be accidently left on. Pretty much any heater for the bathroom should be on a new circuit. They just use too much power and there is alot power needs in the bathroom.

Good luck
 
  #6  
Old 06-25-06, 06:41 AM
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>>Fast-warming 1500W fan-forced heat, 70 CFM exhaust fan and bright 100W ceiling light"<<

If you are just replacing the fan unit, you can probably get away with that model. If you are doing a job considered a remodel, most codes will require the light to be fluorescent.
 
  #7  
Old 06-25-06, 07:41 AM
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Originally Posted by 594tough
>>

If you are just replacing the fan unit, you can probably get away with that model. If you are doing a job considered a remodel, most codes will require the light to be fluorescent.

Where are you at tough. I know the cf's are to save energy but they haven't gotten this anal in NW Indiana or SW Mi yet. Probably is coming though.
 
  #8  
Old 06-26-06, 09:12 AM
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The fixture itself has a 100w maximum lightbulb rating, though we stick a ~100w equiv (23w?) CF in it. Unsure if code requires a cfl or not.

Per your (and the mfg) suggestion, I ran a dedicated 20amp line for this fixture.

So I have power, straight to the 3 gang switchbox.
Is there any reason to go out and buy 4 conductor (3 line + neutral + ground) wire for the run from the switch to the unit?

Or can I just do 3 runs of 12-2+ground, and wirenut all 3 neutrals together?

It'd save me a trip to the store and a few $ on the new wire (have extra 12-2 around the place).

*****

Additionally, the line used to come from the attic, to this switch, then on to a few more outlets.

What is the proper way to 'skip' this switch/fixture as it now has its own separate circuit?
Can I take the incoming line (that used to hit a switch) and tie it straight into the outgoing (next item on circuit) in the same lightswitch gang box?
Or should I run the old line to a junction box in the attic, then a new line from the junction box to the next outlet, bypassing the switch gangbox entirely.. etc.
Clear as mud what my question is?
 
  #9  
Old 06-26-06, 09:17 AM
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As previously stated, you cannot use three separate runs of 12-2. You need to go buy 12-4 or 12-2-2.

Either simply tie the incoming and outgoing wires of the old circuit together in the existing switch box, or pull them up into the attic, install a junction box and tie them together there.
 
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