14/3 inductance problem.

topper
topper Solar Expert Posts: 113 ✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
I installed LEDs a week ago. I have a singled bulb fixture that stays very faintly lit even with the swich turned off. Tested the circuit @ 43vac to neutral and ground..
The light is fed with 14/3, switched on the red wire. White is neutral and black is hot(continues to an outlet farther down the wall)
I have checked all the wiring and even changed the 20' length of 14/3 today to eliminate the chance of a short in the wiring.
The only thing left that may explain this is inductance.
Please tell me I have not lost my mind.
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    Re: 14/3 inductance problem.

    Not inductance. Inductance is the RESISTANCE to AC. That keeps things from working.

    It Might be capacitive coupling from parallel runs. Or leakage across the switch. It might be pickup (again capacitive) if you have high voltage lines near your house. I could feel a faint tingle from the metal trim on my car, parked on concrete, but not on asphalt, from the HV transmission lines across the street.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #3
    Re: 14/3 inductance problem.

    Actually this seems to be a common "problem" with LED lights in off grid systems, or operating on inverter generators. Appears to be the feed through of HF hash from the HF switching used in many inverters, including the inverters in generators that use them. It's not a problem in any way unless you require total darkness. It's just that many LED lights can respond to the tiniest of currents that would never in this world have any affect on either CFL or incandescent lights.
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  • topper
    topper Solar Expert Posts: 113 ✭✭
    #4
    Re: 14/3 inductance problem.

    Thanks guys for putting me at ease. I'm not a dummy with electrical. I just figured I'd lost my mind for a moment.
    Mike, thanks for straighterning out my termanology.
    I was hoping others have had the same problem or similar problems at least.
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  • nsaspook
    nsaspook Solar Expert Posts: 396 ✭✭✭
    #5
    Re: 14/3 inductance problem.

    You could use a SPDT (three-way) switch the sends power when ON but grounds the hot to neutral on the lamp side when OFF to stop the parasitic power glow.

    Modified diagram from Wikipedia without the dangerous second switch. http://en.wikipedia.org/wiki/Multiway_switching#Carter_system
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,658 admin
    #6
    Re: 14/3 inductance problem.

    Do you have a lighted wall switch?

    The little orange neon lamp was enough current that would charge a couple cfl lamps I had and cause them to blink every 5 seconds or so.

    I assume an led lamp would glow from the neon lamp leakage current.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #7
    Re: 14/3 inductance problem.

    Similarly some remote light controllers like the X10 system will do the same thing to CFLs and LEDs. They use a low-voltage pulse (similar to inverters on standby) to sense if the light switch has been turned on.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • topper
    topper Solar Expert Posts: 113 ✭✭
    #8
    Re: 14/3 inductance problem.

    Well it has to be AC coupling. With the switched power and neutral wires disconnected at the light switch, I still have 40+ volts and 3-5mA.
    I know all my wiring is correct.
    Thanks again guys and gals alike.
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