mivey
Senior Member
No. I have no doubt it can read phanton voltage. With a typical multi-megaohm input you can get that. What you need is a lower impedance to be able to distinguish between phantom and leakage voltage.
Interesting Case of Phantom or induced voltage
- Thread starter Dennis Alwon
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kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Low impedance meter draws enough test current to essentially short out the source of the phantom voltage.
High impedance meter doesn't draw enough to bring that source down.
Low impedance meter draws enough current it will shock you if you get in the test circuit path, high impedance will not.
Low impedance meters I have used draw enough current to be effective GFCI testers so they do draw more then 4-6 mA @ 120 volts.
High impedance meter doesn't draw enough to bring that source down.
Low impedance meter draws enough current it will shock you if you get in the test circuit path, high impedance will not.
Low impedance meters I have used draw enough current to be effective GFCI testers so they do draw more then 4-6 mA @ 120 volts.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
So if this voltage is real and is leaking to the equipment grounding conductor then when I connected the non connected equipment grounding conductor's to a connected equipment grounding conductor it should have tripped a breaker. I guess it can be low enough to not trip it...
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Did someone bootleg the EGC to the neutral somewhere and you are measuring voltage drop on a compromised neutral?
Take measurements between all conductors under varying load conditions, as well as to a remote true ground reference, and with a low impedance meter.
mivey
Senior Member
That is why I like the idea of measuring the impedance of the source of this voltage (see post #7). An ammeter would be revealing: before & after connecting back to panel ground.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
No connections were made to the neutral from the equipment grounding conductor. The equipment grounding conductor conductors were all connected in the switch box and the other ends went to the loads and connected there even though there was no connection back to the panel. The dishwasher was connected with metal flex but it went to a plastic pipe under the sink.
The voltage changed from 4 or 5 v to 38 and even 44V when I turned on the uc lights. This voltage was measured from the unconnected equipment grounding conductor's to the SS countertop. Th countertop had no voltage reading when measured to a real equipment grounding conductor.
I will get back there one day-- it is in Raleigh so it may be awhile before I get back there
Just a thought.
Most of the time doesn't the uc lighting wiring run through the walls where the uc and cabinets are?
Sometimes when cabinets are hung don't they use screws that might be a tad too long?
Is it possible that a scew hit a wire. That the screw is touching a water pipe and the neutral.
That there is a return from other circuits that are on through that neutral to water ground connection but the increased voltage when the uc's are turned on is because it's the uc wire that is damaged and making the connection. ???
May totally be out in left field.
Just a thought
Most of the time doesn't the uc lighting wiring run through the walls where the uc and cabinets are?
Sometimes when cabinets are hung don't they use screws that might be a tad too long?
Is it possible that a scew hit a wire. That the screw is touching a water pipe and the neutral.
That there is a return from other circuits that are on through that neutral to water ground connection but the increased voltage when the uc's are turned on is because it's the uc wire that is damaged and making the connection. ???
May totally be out in left field.
Just a thought
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