Timer switch for bulb heater blown

Discussion in 'Electrical Forum discussion & Blog' started by 98ZJUSMC, Jun 24, 2010.

  1. 98ZJUSMC

    98ZJUSMC New Member

    Messages:
    25
    Location:
    Tunnel Hill, Ill
    Have a electrical problem with a Pass Seymour Timer switch on a bathroom remodel I am currently undertaking. Attached is a rendering of the wiring involved:

    [​IMG]

    To explain, I had turned on the timer for the bulb heater. Worked fine. I went over to the 3-pole switch and hit the NUTONE vent fan switch first and the switch popped loudly and died. There was a small black mark on the back of the switch. Both circuits tripped at the panel. The GFCI tripped also. I pulled the timer switch out. I took the bare hot lead and sent power to the bulb heater. It works fine. I turned on both vent fans at the 3-pole switch and put power to it again, works fine. Nothing tripped and everything works.

    Wondering if anyone can find any wiring problem in that diagram that might have caused this before I put another $29.00 switch back in.

    I did read somewhere, probably here, that putting a GFCI downstream from another GFCI was a no-no. I put one in for the refrigerator because it is right below the shut-off valve for the water line for the icemaker. Probably not necessary and I am going to switch it back out or put in a GFCI breaker. The circuit has worked trouble free for about 2 months since I first ran it. Nothing like this at all. The other point is where I wired two neutrals together at the NUTONE unit from two separate circuits. I would have thought that if this is a problem, it would have tripped the breaker at the panel immediately.


    Thanks, in advance!
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,180
    Location:
    New England
    Are any of the items 220vac? You should not arbitrarily connect neutrals from different circuits. A GFCI shold not be installed downstream from another GFCI. First, it's not necessary assuming it is fed from the load side. You could install it on the line side, but then why since one would protect everything downstream anyway when wired to the load side.

    Keep in mind that a white wire is not necessarily a neutral - it could be a switched hot wire.
  3. 98ZJUSMC

    98ZJUSMC New Member

    Messages:
    25
    Location:
    Tunnel Hill, Ill
    Thanks Jim. Yeah, I'm taking out the refrigerator GFCI. It was a little unecessary overkill and I think this little episode killed my ice maker. The control module doesn't show any continuity and the resistance jumps all over the place on the multimeter. !@%&!@%& it.....it's too hot for no ice.:mad:

    No, nothing is 220/240v.

    Since I jumped power from the vanity GFCI to the Timer Switch, I am going to try a replacement switch and make sure I jump it from the line side. I'm pretty sure I jumped it from the load side, initially.

    The neutrals aren't switched hots. By that, I take it you mean using the neutral as a switch leg back to the switch. I don't like to do that as it easily confuses me when I have to go back and check things at a later date. What really confused me (not too difficult to do) is that everything works fine, in unison, when I send power to the bulb heater directly, bypassing the GFCI.

    I will concentrate on that area.

    Thank you, Sir!
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,180
    Location:
    New England
    Keep in mind that a switched leg could be either black or white. It is supposed to be marked, but that is often omitted (by a red piece of tape or similar). So, it is dangerous to arbitrarily tie all of the same colors together. It's okay to tie stuff onto the load side of a GFCI if you want it to also be protected. You just shouldn't run the output of one GFCI to the input of another.
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