20 amp rated fan timer on 15 amp circuit?

Discussion in 'Electrical Forum discussion & Blog' started by Jeff_08, Mar 26, 2008.

  1. Jeff_08

    Jeff_08 New Member

    Messages:
    34
    Location:
    Chicago area
    Hi-

    I wanted to buy a hardwired wall timer switch for my bathroom's exhaust fan and the hardware store had the one I wanted but most of them are rated for 20 amps. The house is over 30 years old and has a 15 amp supply into the bathroom, and I've looked around and didn't find the exact answer to this so I wanted to get some opinions. Since the supply/breaker is 15 amps can I use this 20 amp rated timer to control the fan? Since it's not an outlet and the fan is the only thing that will ever be connected to it, the load would be less than the 20 amp rating and if I understand correctly that should be fine, right? Thanks for any help.
  2. Bob NH

    Bob NH In the Trades

    Messages:
    3,317
    Location:
    New Hampshire
    The timer can be rated at 100 Amps if you can find one as long as it doesn't have 20 Amp receptacle. The only limit on what is connected to the circuit is the load.
  3. prashster

    prashster New Member

    Messages:
    941
    Timers and switches don't add load to the circuit, but they can blow if they aren't rated for the potential load on the circuit (i.e., the components need to be able to pass the entire load through without frying).

    Your 20a rated timer will work fine.
  4. Jeff_08

    Jeff_08 New Member

    Messages:
    34
    Location:
    Chicago area
    Thanks for the responses. I was pretty sure my understanding of the amp rating on a timer was correct (I'm not an electrician, though), but I wanted to verify it with others than do electrical work more than I do.
  5. frenchie

    frenchie Jack of all trades

    What you wouldn't want to do, is the opposite (a 15-amp switch on a 20-amp circuit).
  6. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT


    Why not? Its legal...
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,802
    Location:
    New England
    Unless the load controlled by that switch was more than 15A...?
  8. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT

    Correct, switches are based on load, not the size of the breaker or conductors...
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