bathroom light/fan operate separately

Discussion in 'Electrical Forum discussion & Blog' started by cosmosteel, May 4, 2009.

  1. cosmosteel

    cosmosteel New Member

    I am trying to have my bathroom light/fan operate separately, with one switch operating the light and the other operating the fan. The power coming to the switch is 3 wire (black, white, and ground). The wire coming from the light/fan is 4 wire (black, white, red, and ground). I have 2 single pole switches. How do I run the wires to the switches so that the light works from one switch and the fan works from the other?

    I draw a scheme of the situation i hope somebody can help me urgently. (i read on a website somebody had similar situation and answer was he hadn't have extra wire to able to do this.)


    Attached Files:

  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    New England
    You may not be able to do it without running a new cable. You need to look in the fan assembly and draw what is there now.
  3. Scuba_Dave

    Scuba_Dave Extreme DIY Homeowner

    South of Boston, MA
    IF power comes to the switch

    Ground continues to each
    Neutral continues to each
    Incoming power goes to each switch
    (Next depends upon which color wire goes where)
    Other side of 1 switch is black wire to one device (fan)
    2nd side is red wire to light
  4. Chrissimms

    Chrissimms Master Electrician

    Cohutta GA
    The wire from the fan is a 3 wire (12-3) with a bare ground, 1st turn off breaker to the fan/light, 2nd remove the fan from the housing to check how the fan is wired up. Should be wired with the black (12-3) wire to the black wire from the fan, the red (12-3) wire to the blue or red wire (color depends on make of fan) both of the white wires from the fan should be wire nutted to the single white (12-3) wire.

    In the switch box.....
    According to the drawing
    Tie all whites together and wire nut
    tie all bare grounds together and put on the grounding screw of the switch
    Black wire (12-2) put on either black screw of the switch
    black (12-3) from fan/light put on bottom gold screw of switch
    Red (12-3) from fanlight put on top gold screw of switch.

    The 12-3 wire to the fan from the switch is the " switch leg"
    The 12-2 wire in the switch box is the input power.

    Reassemble fan and energize.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    According to your drawing you only have one switched wire going to the fan. The black wire is either feeding from the fan to the switch and then on to the rest of the circuit, or power is coming to the switch from the right side and then the black wire is continuing on to the rest of the circuit while the red wire is operating the fan and light. As you said, you do not have enough wires to do the job you want to, unless your drawing is incorrect.
  6. Billy_Bob

    Billy_Bob In the Trades

    Red on the left side of the double switch.

    Disconnect the two black wires connected to that one black wire.

    Connect each black wire to each connection on the right side of the double switch.

    So on left of double switch, red wire.

    On right side of double switch, one black wire to first switch, then the other black wire to the second switch.

    Then green to the ground connection on the double switch.
  7. cosmosteel

    cosmosteel New Member

    I did what Chrissimms told and when i did that i see one button controlled light and fan and the other one receptacle on the wall. So i think light and fan connected above so it is an advanced job for me to do. Like most of you said it needs an extra wire.

    Thanks a lot all.
  8. Billy_Bob

    Billy_Bob In the Trades

    Well this would be a small easy job for an electrician even if you have to add an additional wire.

    So should not be too expensive if you call an electrician to do the work.
  9. Alectrician

    Alectrician DIY Senior Member

    689's not gonna happen.

    The hot power appears to go out to your light JBox and then out to other lights/receps.

    Your options depend on the structure. You need to get from the light JB (probably) to the switch box. You could also (probably) go from the light Jbox down to a new switch location for the fan switch. If it's an old school installation with a wall light above a medicine cabinet, the installation is pretty easy. Just take out the cabinet and you open up access to the wall.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    I fail to see how adding even a single wire in a house wired with Romex, would be a "fairly easy" job, for anyone, unless it has the attic above it for access. In this area, most attics are either non-existent, or difficult to access.
  11. prashster

    prashster New Member

    I'm missing something in your diagram or in the responses given so far.

    IF your fan has a black and a red, then one powers the light and one powers the fan.

    If both of those wires are making into yr switch junction box, then you just have to wire one switch's load side to the red, and the other switch's load to the black. Then attach incoming line voltage to the incoming line sides of each switch.

    I've done this on all my ceiling fans and it's worked as expected.

    The existing wiring looks like either the fan or the light (whatever's wired to black) isn't switched at all; the switch is only operating the red. If in your fan box, the line black is capped and the red and black to the unit are pigtailed, then your switch would operate both devices. So, to operate independently, make sure your red and black are not tied togther in the fan box.
    Last edited: May 6, 2009
  12. Billy_Bob

    Billy_Bob In the Trades

    Well they make long flexible 5 ft., 6 ft. drill bits with holes in one end. You can drill up into a wall and then fish wires back down. Or drill sideways in a ceiling and fish wires across. Quite easy if you have the right tools.

    These drill bits are available at an electrical supply.
  13. Alectrician

    Alectrician DIY Senior Member

    You are thinking of a ceiling fan. His situation is a bit different. Blk is hot, red is switch leg to his bathroom light/exhaust fan.

    The black wire is constant power.

    If it's an "old school" installation with a wall light above a medicine cabinet, the installation is pretty easy :D

    You are a plumber and you have been around for a while.....right?

    Picture this.

    Bathroom has a recessed med cabinet with a light on the wall right above it. If you are really lucky it is one of those 6" plumbing walls framed with offset 2x4's.

    His wiring description sounds like there is both the light switch leg and power in the light jbox. The fan sw leg would also come from the sw box.

    You pull out the med cabinet and take down the light fixture.

    You have power in the JB as well as the fan sw leg.

    You also have pretty good access to the wall cavity via the med cabinet niche. You just need to get from the light JB to a new switch location below it and install your ex fan switch/timer there.

    If it IS an offset 2x4 plumbing wall you can easily fish across the wall to locate the switch left or right.
    Last edited by a moderator: May 6, 2009
  14. cosmosteel

    cosmosteel New Member

    Thanks for all ideas. Yesterday i checked fan box and decided to put a pull chain switch inside the box and that was easy i have no idea what is what behind the walls and i did not want to ruin the paint and wall.
  15. Thatguy

    Thatguy Homeowner

    Does X-10 home automation make modules for this? The receiver would need to be mounted inside the fan housing to decode the fan/light signals.
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