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I was recently working on my ceiling fan wiring. I had the breaker off and I confirmed no power coming in. While I was preparing to twist the cap onto the black wire (I was touching the exposed copper), the electric heat in my house kicked on and I got a smallish shock.

The shock wasn't as significant as touching a live black wire; if I had to guess I'd say half as painful.

Is this an indicator of a problem in my house's wiring?

  • Is this electric baseboard heat or central heating? – ThreePhaseEel Jan 18 '18 at 0:51
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This might be due to loss of the neutral connection before the entrance panel. If the lights on some circuits get brighter and others dim when the heat turns on (or other high-current device starts), this would confirm that the neutral line is floating, i.e. the voltage on the wire, rather than being at nominal ground, is determined by the current drawn across each of the two main circuits.

If you have a multimeter, you can confirm that the neutral line is within a few volts of ground... not enough to give you a shock, unless you you contact wet skin or a cut. If the voltage goes above that for more than a second, you should contact an electrician to check and repair the neutral line.

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Well it really shouldn't matter if you have the breaker off but in years past a multi wire branch circuit did not require handle ties or common trip. This may be the case and you turned off 1 breaker but the other breaker was still using the neutral any imbalance will be on the neutral, or the hot on the circuit you thought was turned off gave you a shock. Been there in residential and industrial. Current code protect for this with a common trip on these kind of circuits.I will need to find my 80' S code books because there was no dedicated circuits back then and if on what we call a MWBC today handle ties were not required. Edit i was an apprentice in the 70' S back when zinsco and FPE was the the best or low cost options avabile did lots of them in my apprenticeship and after returning home.

  • Electric heat should be on dedicated 240V and should not also involve MWBC. – Harper Jan 18 '18 at 2:19
  • I will need to find my 80' S code books because there was no dedicated circuits back then and if on what we call a MWBC today handle ties were not required. – Ed Beal Jan 18 '18 at 2:27
  • In case it matters, the house was built in 2002. – GaTechThomas Jan 18 '18 at 6:03

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