I've got one of those 'blinking beeping light' tools that detects when voltage is present.

I was switching out a light and the switch was off, but the tool beeps even with the switch off to the hot wire. Got out my meter, shows .01 volts, turn the switch on, shows 123v. Measured at the switch, shows the same.

How is current feeding/bleeding through? Is this dangerous? Its been like this for 12 yrs or better on a new home. Breaker is off today.

This circuit only has 1 outlet, 1 outside light, 1 interior light

I've traced it down to a section of wire or junction box. Removed the outlets, lights (thought it might be a bad switch/light, but it wasn't).

Overall I think at the junction box, maybe someone clamped the wires down to tight???

Neutral/ground has no voltage.

Let me know what you guys think, Thanks. John

 

you could have a transient voltage bleed thru from another circuit where the wires are wound around each other, like in the panel where the wires are stripped back for tying into the breakers. .01 volts is nothing to be concerned about. A lot of times when we run low voltage wiring for digital controls in A/C work, we have to make sure we are using shielded wiring so our low voltage wires do not pick up transient signals from other high voltage wires we cross or run in proximity to our wires...

 

To read that small of a voltage you have to be using a high impedance digital volt meter.

The conductors as they run throughout the house are basically acting like a small capacitor. They meet the definition of a capacitor perfectly, two conductors separated by an insulator.

Basically when you put the meter between the conductor and another conductor you're completing a circuit. Since you're completing the circuit and have a very tiny current flow across a very high impedance (from your meter) you will show a voltage.

0.01 volts is nothing for a phantom voltage! Its much more common to see a few volts but you can see much higher. I saw one before that was in the 50V range. However connecting a low impedance solenoid type meter like a SqD Wiggy caused it to disappear.

If you have the instructions for the meter it probably will cover phantom voltages in there somewhere.


http://www.nema.org/stds/eng-bulleti...ulletin-88.pdf