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something weird happens in my house. I switched off the main circuit breaker for the house in order to change some light sockets and surprise - when i double checked with AC voltage tester I got positive on the light bulb socket. Not only that, I tried few more places - the tester detects power everywhere, but not only on the hot wires - the neutral ones started to trigger my tester too (before switching the breaker off, and after switching it on again i got power only from the hot wires only). I know the tester is good, as i have small diode indicator on the light switches and they are still working after turning off the main breaker. No lights or electric appliance worked tho, so i think it's some low voltage current flowing. So it seems when my main breaker is off - not only the power is still on, but it's flowing in the neutral wires too. What could be the problem?

Update: Every reading was measured also with phase meter and multi-meter with the same results.

Thanks!

Update 2: Photo of the circuit board with the breakers (old school): enter image description here

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    could be inductive power. Does the light actually come up? – yo' Jan 23 '17 at 14:48
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    DC? Where are you on the planet? What electrical system? – Tyson Jan 23 '17 at 14:50
  • How long have you had the house? Is this the first time this has happened? Is the electrical service simple, or are there other boxes/control panels as well as the one you turned off? – Yehuda_NYC Jan 23 '17 at 14:50
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    How many volts are you reading? – Tester101 Jan 23 '17 at 15:07
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    Can you post a picture of your inside board? – Tyson Jan 23 '17 at 15:41
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It's possible the panel you have illustrated is one of several such panels serving power into the unit, so you may need to do an exhaustive search for any others.

It complicates things if this building has more than one unit. Wiring to the other units could be still energized obviously... And this could create false readings on test equipment (capacitive coupling) -- or there could be actual cross-connection between the units, so your unit might not be fully de-energized unless others are too.

Cross-connection could be a load in your unit served out of their circuit... Or even a neutral cross, where their load is served from their panel, but it uses the neutral on your panel, and if you sever that neutral wire which has current flowing through it, the upstream side will be energized to 230V.


A lot of testers are complete junk, or are not made for house wiring and need some skill to successfully apply.

A common night light is surprisingly useful. It is simple, honest and not particularly reliable, which means you must check and double-check it. I honestly find them more useful than 3-lamp testers, though those are OK for a final check for new outlets.

Plain old analog voltmeters with the moving needle are useful.

Digital voltmeters (DVM) are useful but a little tricky. They are so sensitive they can pick up micro-currents from capacitive coupling, which happens when a dead wire runs physically parallel to a still-energized wire. So you have a DVM a reading of 109 volts on a 120V circuit that you thought was turned off - plug a night-light in, and the voltage mysteriously disappears.

If the electricity is powerful enough to illuminate any light, even an indicator light -- that's not capacitive coupling, that's genuine power.

  • thanks for your answer. I am not sure if the voltage disappears, the light just doesn't light up. I suppose it's because when i remove the main breaker, as i pointed - the neutral wire receive 10V current, so practically I have 2 hot wires and no neutral (just a theory, as nothing makes sense in my case). For the main breaker - it's turned off for sure, as every single light/appliance goes off when i remove it, although there is still electricity everywhere if i believe my testers and the working indicator lights on the light switches. – ePetkov Jan 23 '17 at 16:31
  • Btw The DVM are reading 220V on 220V circuit. The phase meter is how we call here the one contact neon test lights, it doesn't give voltage, just indicates that there is power (like this one: en.wikipedia.org/wiki/Test_light#/media/…). The AC tester i use is similar to this one: en.wikipedia.org/wiki/Test_light#/media/…. The building has only one unit, so i have no idea if the cross-connection problem could exist in one unit houses. – ePetkov Jan 23 '17 at 16:33
  • you can have a cross connection problem if you have two panels. For instance my house has an obvious fuse box, and a hard-to-find retrofit breaker panel. You never know what's on which. – Harper Jan 23 '17 at 17:46
  • is the cross-connection problem explaining the trace of electricity in the neutral wire when the main power breaker is off? – ePetkov Jan 23 '17 at 17:56
  • Definitely possible. 10V seems kind of high for a neutral, I would expect it to be closer to zero (but not zero unless everything is off). Thing is, your panel looks awfully small, and I suspect that similar to my house, they added more circuits by adding another panel elsewhere. – Harper Jan 23 '17 at 18:06
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If the Neutral is disconnected but the live wire is not and any appliances are connected then the Neutral will become live.

I guess your indicators are connected between Live and Earth and that is why they continue to operate, I have no idea if that is/was considered acceptable practice where you live.

There are several possibilities, one is that your "Main breaker" is faulty, another is that someone has wired up a device that takes it's Live from somewhere other than your "main breaker" but it's Neutral from your main breaker.

Either way extreme caution is needed when working on this installation.

You really need to get this looked at by someone who is familiar with local wiring practices where you live. I guess from the writing in your picture you live somewhere in the former Soviet Union and I doubt many people here are familiar with Soviet wiring practices.

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