Ghost Voltage

[khalida]

We have recently installed 120/208V panel, our electricians are seeing when checking at 20A/1P breakers using different meters they are reading ghost voltage of up to 100V, what do we need to check for and what we need to do to eliminate this ghost voltage.

 

[ATSman]

Use a low impedance VM such as a Knopp or Wiggy. If it is induced voltage it will go to zero.

 

[ActionDave]

You need to check for proper wiring. If it is ghost voltage a low z meter or a load on the circuit will make it go away.

 

[ATSman]

Knopp tester

Knopp tester

see attached

 

[tom baker]

While popular, a wiggy or knop is not a safe meter to use on circuits with high fault current levels, they don't have double shrouded leads, etc.
I use a fluke t+pro, lights up, vibrates, does ohms, has a light, tests GFCI, slices, dices, its only 19.99, but wait if you buy now you can get a second one for only the cost of shipping and handing...
A Fluke 115 has a low Z function and Fluke sells plug in low z devices that load the circuit, its a fluke SV225

 

[jim dungar]

Fluke has an application note on Ghost Voltages.
http://support.fluke.com/find-sales/Download/Asset/2105317_A_w.pdf

 

[ptonsparky]

A Ghost voltage of 100 is pretty high. I’m inclined agree with ActionDave. Check wiring.