Neutrals all capped off in a light switch box for a fan

vegan_vicky

I have a ceiling fan in my dining room that's controlled by a simple light switch. I wanted to see if I could upgrade the switch to have separate fan and light control. I opened up the box and I saw that there were 3 sets of Romex 12/2 entering the box. From the light switch, the bottom terminal was pigtailed to the two black wires from the right of the box and the upper terminal was pigtailed to the black at the left of the box. I thought one...

Originally asked by SMF44 on Stack Exchange (diy) (CC BY-SA 4.0).

uphilltech

Great question — answering as the UphillTech team:

I can think of 2 possibilities that would explain your old situation (neutrals capped off, but everything appears to work), but both of them are a big No-No and should be rectified. The fan and kitchen outlets took their neutral from another circuit. This is not allowed, because it can overload that neutral wire (causing a fire) and the supply and return currents for the fan and kitchen take different paths, which causes electromagnetic interference. The ground wire was re-purposed as neutral. This is not allowed, because the ground wire is only supposed to carry current when there is a fault in the electrical system. You should inspect the fan box and the kitchen outlet boxes to see where...

Full answer by Bart van Ingen Schenau: https://diy.stackexchange.com/a/331974 (CC BY-SA 4.0).

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