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Thread: New motion sensor light switches

  1. #1
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    New motion sensor light switches

    Have they changed the way they manufacture motion sensor switches, since they changed the code to where you have to have a neutral in the light switch box? I am rewiring an old residential house and hooked up a single pole motion sensor switch, two hots and a ground, I had to ground the ground wire to the metal box, but it didn't work? What's the deal its just a simple single pole switch? Put one of these in my own house before they changed the code and it worked fine.

  2. #2
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    Did you get the line and load correctly connected? Unlike the no-neutral-required units, it matters.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

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    Yeah, there was no neutral with it, only line, load and ground

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    How old is this house? Does it have an EG in that metal box?

    I don’t recall coming across a switch that has two ‘hots’ and a ground. Admittedly I have not installed a newer motion switch lately but it sounds like you are describing an older switch that utilized the EG to function. Some would also pass a small amount of current through a lamp filament to work. Make & model # of the switch?
    Tom
    TBLO

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    Sounds like you don't have a real equipment grounding conductor or equipment ground.
    They say I shot a man named Gray and took his wife to Italy
    She inherited a million bucks and when she died it came to me
    I can't help it if I'm lucky



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    190602-0748 EDT

    Eddy Current:

    First, you need to understand how devices work that you use.

    That means you should know electrical circuit theory, how basic components work, take complex devices apart and study what is inside, and run experiments.

    Consider a simple electromagnetic relay. It is a binary device. This might have a NO and a NC contact, and a coil. It takes no input power to be in one state, and a certain amount of power maintained to be in the other state. There are some relays that are bistable latching, and only require transition power to change state. The GE RR-7 is bi-stable latching, and has a set coil and a reset coil.

    There are solid-state relays that require much less control power to change state than an electromechanical relay of the same current rating.

    If you have a two terminal device how are you going to get power and maintain the power to operate the relay?

    Take your photocell apart and trace the circuit. Run bench test experiments on the control, and see how it works.

    .

  7. #7
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    Quote Originally Posted by ptonsparky View Post
    How old is this house? Does it have an EG in that metal box?

    I don’t recall coming across a switch that has two ‘hots’ and a ground. Admittedly I have not installed a newer motion switch lately but it sounds like you are describing an older switch that utilized the EG to function. Some would also pass a small amount of current through a lamp filament to work. Make & model # of the switch?


    No, and it was built in the 30's

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