15.6V Showing on Circuit - Why??

Discussion in 'Electrical Forum discussion & Blog' started by nasttcar, Jul 10, 2007.

  1. nasttcar

    nasttcar New Member

    Jul 10, 2007
    I am showing 15.6 volts on my outlet hot wires, even though power is not on that circuit.

    Here's the background.

    I have just put in a new room in my basement. The room has 6 outlets around the perimeter and 10 "can" lights in the ceiling on 2 switches.

    All electrical is run in conduit and the hot wire comes from a 20A circuit and all wiring is 12ga. solid copper. All is installed in metal boxes.

    All commons are twisted tightly together and wire nutted.

    I used a blue wire for one light circuit, a yellow wire for the 2nd light circuit, and black for the wall outlets.

    When I have the lights on in the room, I get 15.6 V showing on the black wire for all of my wall outlets.

    Because all of this is now behind sheetrock, and several of the runs are through flexible whips, it is impossible to pull out or pull back any of the wires.

    What is going on, and what are possible solutions?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Sep 2, 2004
    Retired Systems engineer for defense industry.
    New England
    Are they all separate CB? or are they all on one CB? Is there one common neutral, or did you run separate neutrals for each branch?
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  4. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Nov 8, 2005
    Hansville, Washington
    What kind of meter are you using to measure the voltage?

    Are the can lights and receptacles all on the same 20A circuit from the panel?

    Do you see the same 15.6V at the recptacles with the lights on and off?

    If the current-carrying conductors to the lights and the receptacles run alongside each other for any distance, I'm suspecting a small induced voltage on the hot lead to the receptacles coming from the current flowing to power the lights. With no load on the receptacles and a sensitive meter, you will see that voltage. Try plugging in a small lamp or other load and I'll bet the voltage drops to essentially zero.
  5. BrianJohn

    BrianJohn DIY Senior Member

    Jun 22, 2007
    1. What conductors are you measuring the voltage betrween?
    2. Is the power on to the outlets when you measure this voltage?

    I f the answer to 2 is the power is off and you are using a digital meter see
    Mikey's post above he hit the nail on the head, commonly called "Ghost Voltage" this is not uncommon.

    Take a wiggy type tester (solinoid style) or plug in a lamp, look closely at the lamp (clear bulbs work best) see if the bulb shows any light (red) also measure voltage at this time.

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