Very simple home wiring question

Discussion in 'General Electronics Chat' started by ejmmende, Feb 1, 2008.

  1. ejmmende

    Thread Starter New Member

    Feb 1, 2008
    1
    0
    Apologies for the simplicity of this post -- Just installed a new ceiling lamp -- black connected to black - white to white and colored to colored. Bulb lights up, but now stays lit regardless of the wall switch off or on....both up and down the bulb stays lit -- what did I do wrong?
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    When you speak of the wire connections, I am assuming they are for the connections at the lamp fixture, and that you did not alter wiring at the switch.

    Two possibilities come to mind. One is that the switch is interrupting AC common rather than hot. With the lamp having power to it all the time, some wire came loose and is making a path in parallel with the switch. You would need a meter to check for this condition, and be aware that if the switch is miswired as I have suggested, a potentially lethal voltage will always be present in the lamp fixture.

    The second is much smpler - the wall switch decided to fail on at just that time. This can also be checked with a meter, but it would be a good idea to trip the breaker supplying voltage to the ceiling fixture and double check with the meter before doing much poking around. Place one lead to ground - the green or bare copper wire, and see if there is any voltage reading to the black and then the white wires. If not, the circuit is isolated.

    Once things are exposed and stable, you can turn the breaker back on and repeat the voltage test. Only the black wire should have any voltage - anywhere from 115 VAC to 121 VAC is normal. If the white wire has any voltage on it at all, then there is a problem with the house wiring. You might want to get an electrician out to find out what is not wired correctly.

    Be sure to turn the breaker off before closing up the fixture. Move slowly around exposed wires.
     
  3. eeboy

    Active Member

    Sep 27, 2007
    90
    1
    Is there another conductor located at the ceiling (lamp)? Possibly a red conductor (assuming romex)? Often times there will be 4 conductors:

    White->Neutral
    Black->Hot Leg
    Red(or other color)->Switched Hot Leg
    Green or Bare-> Ground

    If this is the case you would simply need to swap the black out for the red. Make sure you place a wire nut over the unused black so that it does not make contact with the junction box (or anything else).
     
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