My light switch reversed... polarity???

Discussion in 'Electrical Forum discussion & Blog' started by Fistor, Mar 21, 2011.

  1. Fistor

    Fistor Geotechnical Engineer

    Messages:
    48
    Location:
    Vancouver, BC
    Hi all -

    A while since I've been here, but I have a strange "problem", if you will, that popped up a few weeks ago...

    In my kitchen, I have a lightswitch that operates a single, overhead light (a fluorescent bank). I've lived in this house now for 6 years, and until a few weeks ago, everything was 'normal', with a down position of the switch corresponding to off, and the up position corresponding to on.

    A few weeks ago, I went to turn on the light by flipping the switch up, only to find that it was in the up position. Thinking the breaker had triggered (or less likely, the fixture itself had failed), I flicked the switch down, only to have the lights go on!

    This is an older house (1951 or so), with some remnant of older wiring still present. The logical thought (at least to a layman like me) was this this must be a 3-way switch, with the other switch somewhere that I have never discovered, or encountered before... yet I know of and cannot find any such switch, and this has never happened before. I went and tried every possible candidate that could be the "other switch", maybe something in the basement, but nothing.

    Has anyone every heard of such a thing occurring? Is there some other reason this may have occurred? I have yet to open up the switch itself, and to be honest, feel a little leary if I am unsure of whether another switch may be present... also, is this an indication of a potential hazard? It might be difficult in this older house to figure out what happens with the wiring between Point A (the panel) and Point B (the switch).... :confused:

    All help appreciated!

    Thanks, Carl
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,185
    Location:
    NW Ontario, Canada
    Pop the cover and count the wires. If it has more than 2 wires, look for another switch.
  3. Fistor

    Fistor Geotechnical Engineer

    Messages:
    48
    Location:
    Vancouver, BC
    Ah, great point hehe, I'll check when I get home - thnx for quick reply.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    Look at the switch. If it is a single pole, and not a "Decora" style, it should have "on" and "off" printed on it, and would be impossible to reverse the function. But you are describing a three way switch and the other one was used to turn the light on or off, which reversed the function of the one you usually use.
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