26 VAC leakage?

[stewart]

Hello

I've seen this before in the old house and I'm seeing it again in the new one. On circuits that have been shut off at the breaker, I can read 26 to 36 VAC across the black wire and neutrals or earth ground. Anybody have input?

Thanks Stewart

 

[Ironcrow]

Yes, digital voltmeters can read bleed-over from adjacent wires. There is hardly any current available at this ~30 volt level. Even the impedance of a cheap analog volt meter will pull the voltage down to nothing.

 

[Stuart in MN]

If you're using a digital voltmeter, chances are you're seeing a phantom voltage. It's nothing to worry about. http://en.wikipedia.org/wiki/Phantom_voltage

 

[stewart]

Thanks for the replies.

Stewart

 

[ddawg16]

Phatom voltage is not exactly the right description....

What you are seeing is 'induced' voltage. This is a good example of what happens when wires pass parallel to each other over a distance.....I have seen as much as 80-90 Vac....

The good news is that it's a low current....if you grab the wires, in most cases there is not enough current for you to feel anything.

 

[TurnipTruck]

I see this at the plant all the time. I recently had a problem at work where a 120Vac relay was intermittently energized by induced current when a strobing DC signal RUN IN THE SAME 1000' CABLE AS THE AC POWER caused mystery shutdowns. I measured 80+ Vac with the far end of the AC wires disconnected.

 

[LoneGunman]

That's why I still use an old school "wiggy" (solenoid operated tester) as my main tester, no reason to break the expensive Fluke out for 99% of jobs and the "Wiggy" won't read low current voltages because the solenoid is using the current.

 

[stewart]

What do you mean by "solenoid operated tester"? Is this the needle type?

Stewart

 

[Stuart in MN]

A Wiggy is a go / no go tester that just indicates if there's power or not:

http://www.squared.com/us/products/machine_safety.nsf/unid/58870E11543C976885256D500050927B/$file/wiggy.htm

An old style analog voltmeter also works well.