New one on me.

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monkey

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Arizona
I do a lot of remodel work. Today I was sorting out all the old wiring after the demo crew had removed the sheetrock. There was a fan box with a big black scortch inside. The home owner said he got shocked in that box when the breaker was off.

Well the box contained one 14/2 home run, another 14/2 wired to two breakers, going off to two more circuits, using the neutral from the first 14/2 home run. So we had three circuits in the fan box, all sharing one neutral, and in different cables.

The homeowner explained that in a previous bathroom remodel a "new" circuit had been added.
 
In my home, built in the late 80s, there is a dodgy shared neutral arrangement for a wall light in the lounge. Theres no evidence that this anything other than original construction. I was changing the wall light to something prettier, and got belted. Couldn't believe it, the first shock I'd had in decades and in my own home.

The neutrals were basically just wrapped together and put under a single screw. Replaced it with a pigtail arrangement; its still an unsatisfactory job, but I'm not ripping the house apart to fix it.

Edited to add: Yep, prior to starting work I'd checked there were no voltages on any of the wires with respect to ground, which of course there wasn't, as the neutral circuit was intact, until I separated the wires...
 
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monkey said:
I do a lot of remodel work. Today I was sorting out all the old wiring after the demo crew had removed the sheetrock. There was a fan box with a big black scortch inside. The home owner said he got shocked in that box when the breaker was off.

Well the box contained one 14/2 home run, another 14/2 wired to two breakers, going off to two more circuits, using the neutral from the first 14/2 home run. So we had three circuits in the fan box, all sharing one neutral, and in different cables.

The homeowner explained that in a previous bathroom remodel a "new" circuit had been added.
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Dont worry they say Arizona is a DRY heat.
 
dbuckley said:
Edited to add: Yep, prior to starting work I'd checked there were no voltages on any of the wires with respect to ground, which of course there wasn't, as the neutral circuit was intact, until I separated the wires...
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That's exactly why they want handle-ties on MWBC's these days.
 
LarryFine said:
That's exactly why they want handle-ties on MWBC's these days.
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But how does that work with 3 hots? :grin:

Assuming it was wired as I read in the OP, there was H, H, H, N coming from the panel. Load up the two hots on the same phase with little load on the third, and you have a neutral space heater. Of course, there might be 3-phase in this house, in which case it's all good, save for the pair of 14/2s in place of 14/4... :grin::grin:
 
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Handle ties still won't help where someone has tagged onto a convienient neutral somewhere. I have a habit of holding my Fluke non contact tester to the neutrals as I separate them.
 
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