Sub panel

[ADELECTRICWORKS]

Hi, I am installing new circuit on a sub panel. Running 12/3 mc. I plug in black into the 20 amp breaker. No other wire is connected to anything else. Green, white and red is not connected in the panel. Load side is not connected to anything. As soon as I turn the breaker on. I have 55v in green & white.
Same thing with red conductor also.

 

[LarryFine]

That's the result of using a high-impedance voltmeter which uses so little current that it's reading induced voltages. If you connected a small 120v bulb between any of those floating wires and ground (i.e., in parallel with the meter), it would provide enough load to make the meter read zero.

 

[ADELECTRICWORKS]

That's the result of using a high-impedance voltmeter which uses so little current that it's reading induced voltages. If you connected a small 120v bulb between any of those floating wires and ground (i.e., in parallel with the meter), it would provide enough load to make the meter read zero.

Thank you Larry, but nothing is connected there is no path between wiring

 

[readydave8]

I'd be surprised if same tester ever showed zero, try it on unenergized traveller on a 3way switch

 

[roger]

Thank you Larry, but nothing is connected there is no path between wiring

Nothing needs to be connected. Do as Larry said or take a solenoid type tester and parallel it's leads with the meter you are using now.

 

[kwired]

Thank you Larry, but nothing is connected there is no path between wiring

it is called capacitive coupling.

A capacitor is constructed with two or more sections of conductive material separated by insulating material. Thin layer of insulation and the surface areas are what determine the capacitance value. Your conductors in the cable are not a great capacitor, they won't store enough energy to be of much practical use but they still inherently are a pretty weak capacitor.

It is a weak enough capacitor that if you use a low impedance meter to test voltage the current drawn by your meter though pretty low is still enough to drain the capacitor to give you a zero voltage reading. You could get a zero reading with a high impedance meter just by connecting a resistance in parallel to your meter leads that resistance can often be in the thousands of ohms range and it will still draw enough current to basically eliminate the voltage stored in the "capacitor".

 

[LarryFine]

Hi, I am installing new circuit on a sub panel. Running 12/3 mc. I plug in black into the 20 amp breaker. No other wire is connected to anything else. Green, white and red is not connected in the panel. Load side is not connected to anything. As soon as I turn the breaker on. I have 55v in green & white.
Same thing with red conductor also.

Note that the 55v is approximately halfway between the 120v of the energized wire and the 0v of the grounded sheath of the cable. The floating wires exist in a virtual voltage divider.