Exhaust Fan Replacement Timer

Discussion in 'Electrical Forum discussion & Blog' started by Shrapnel, Aug 24, 2007.

  1. Shrapnel

    Shrapnel New Member

    Hi, I'm replacing a conventional switch in the bathroom which controlled the exhaust fan. I am placing a timer instead. Upon opening the switch box, I noticed that I only have 1 - black, 1 - white, 1 - bare ground. Therefore, I assume the source is at the fixture.

    Exhaust fan is 13 Amps, therefore I figured I needed a 20A Timer (requires white neutral connection). Now, my question is, if the source is at the fixture (fan), would it be safe to use a 5A Timer (which doesnt require a white neutral connection)? If not, how do I connect the timer without access to the extra wire.

    Hope this makes sense, I am new at this.

  2. Chris75

    Chris75 Electrician

    Litchfield, CT
    Is this a residential exhust fan? Also if this fan actually draws 13 amps, this will definitely be a problem with a 5 amp switch....
    Last edited: Aug 24, 2007
  3. jwelectric

    jwelectric Electrical Contractor/Instructor

    North Carolina
    I see the sheet rock pulling off the walls and the commode lid standing straight up every time the fan is turned on.
  4. Furd

    Furd Engineer

    Wet side of Washington State
    A bathroom fan that is rated at 13 Amps probably has a heater too.

    Why not use a spring-wound timer?
  5. leejosepho

    leejosepho DIY scratch-pad engineer

    If those black and white wires were/are connected to the switch, I would guess the black is hot and that the white carries power from the switch to the fan motor already connected to a common (white) on the other side of its windings.

    As others have already suggested, that is very unlikely ... and here is a nice timer to consider once you get the amperage issue sorted out:

  6. hj

    hj Moderator & Master Plumber Staff Member

    Cave Creek, Arizona

    If the timer has a separate neutral, it must be electronic, so unless you can extend a neutral to the timer you cannot use it. Why not use a mechanical timer that has a knob that turns to the amount of time desired with a maximum of say, 30 minutes?
  7. SteveW

    SteveW DIY Senior Member

    Omaha, NE

    I'm with Furd and hj on this. Any good hardware, or big box, store will have a variety of spring wound timers, with different max. durations (some up to several hours).
  8. leejosepho

    leejosepho DIY scratch-pad engineer

    Ah, yes, I missed that.
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