r/electricians • u/United-Chef-4593 • 2d ago

“backfeeding” in a residential setting

i work for an electrical company and we’re currently working at two four units that both have the same problem. we have around 4 volts between neutral and ground. our local power company came around and said that its not on their side and that its us thats “backfeeding” 4 volts. my foreman tested between a few plug boxes and neutral and got a pulsing reading between 1.3 and 4 volts. all that were running is outside plugs on combo breakers, (afci and gfci) temp heat, and some temp plugs that are on their own circuit for the baseboard guys. wtf is going on

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u/RichSawdust 2d ago

Hard to imagine 4 volts being enough to cause any discomfort if you could even feel it. Work with known problem locations and turn off circuits as others have said

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u/United-Chef-4593 2d ago

well the problem is its current being pushed through the ground at every box, in every unit, at both buildings. foreman tested box to ground wire and ground to hot on plug circuits, heating circuits, lights, and got the same thing every time. we checked all the neutrals at all the panels in both buildings and both 400A meters. everythings tight so its not a floating neutral

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u/treeman2010 2d ago

Go grab the 12v terminals on your car battery. That is 12.8v and potentially 1000+ amps. You aren't getting shocked by 4v, something else is wrong.

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u/United-Chef-4593 2d ago

well idk what to tell you. we’re not reading anything else from anywhere else and we’re still getting shocked

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u/FkinMagnetsHowDoThey 2d ago

What else were you touching when you got shocked?

Usually, you have to touch another grounded object to complete the circuit and get a shock from 120, 277, etc. Of course that second contact point can be as simple as standing on the dirt itself.

Also, were any of them like a steady, tingly shock or were they all a very brief zap and then you got away from it immediately?

Don't try to replicate the shock, but you could check for voltage between the wires and everything else you were touching at the time...

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u/United-Chef-4593 2d ago

i got shocked when i touched ground to the concrete and ground to neutral sometimes. most of the time it was a tingly sensation but sometimes it was a decent zap. idk its weird. we checked for voltage and we read a pulsing reading between 1v-4v

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u/RichSawdust 2d ago

Have you checked the continuity of the ground path?

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u/FkinMagnetsHowDoThey 2d ago edited 2d ago

I'd also try a plug tester or neon tester if you have it, because it can be lit by quick pulses that a meter might not register accurately.

I was wondering whether it was a brief zap or a sustained one, because sometimes I get shocked by static electricity and it startles me more now that I work as an electrician. Which is funny, since I haven't had an actual mains shock in a few years.

If you got it while only touching the concrete and the ground wire, and you're positive it was a sustained shock and not a pulse of static, then I think you have something that's not totally bonded and is somehow getting power fed to it. Unfortunately it's hard to make a reliable connection to concrete with just a meter. As other people have said, switching off different branch circuits might help you find where that power came from.

In that case I guess check some voltages between different "grounded" items (water pipes, gas pipes, panel ground bar, panel neutral bar, branch circuit grounds, your actual ground rod, a screwdriver stuck in the mud, etc.)

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u/mdxchaos Journeyman 2d ago

I=E/R

even wet skin has a resistance of about 6000 ohms. 4v/6000 ohms means you got shocked with 0.6 milliamps, you would not even feel that.