3 way confusion

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dm9289

Industrial Maintenance Electrician
Location
Pennsylvania
Occupation
Industrial process repair/ maintenance Electrician
I know this is not really a code question but it is some phenomenon that was bugging me. I recently hooked up a couple of three way circuits with no fixtures and was using my proximity tester to verify operation my proximity sensor always indicated power. My first impression was that i made some wiring error, I rechecked and all was Ok. So I used a DMM to check actual voltage with power on I had 120v when off I had 32v so once again I re-checked the circuit wiring it was OK. So i hooked up a temporary light it went on and off as expected, and with the bulb in when off there was no voltage, took the bulb out back to 32v. I next suspected maybe the 32v was not compatible to light this lamp so I checked it on a dimmer circuit and it provided illumination at as little as 5v. Maybe someone could straighten me out.

Thanks as always
Dave
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
I suggest digging out an old solenoid based wiggy or a d'Arsonval coil meter (a cheap mechanical volt ohm meter with coils and a needle). Then use a "known ground" like a single wire from the EGC (equipment grounding conductor) somewhere close. Redo your open circuit measurements, and you'll find very different readings.

Digital voltmeters and voltage detectors have sensitivities to "phantom" voltages that come for capacitive coupling with energized conductors in close proximity.
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
The phantom returns.... Does the Nuetral run with the travlers? This may minimize this in the future.
 
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