I have an old house where one of the light switches was run with one run of 12/3 cable. The black was on the hot and the white was on the load. Is this dangerous? I went up to the attic to find the run and it looks like the neutral was spliced there. The switch operates just fine and it only controls one light.

On the 12/3 cable, what are colors of wires?

Chuck

If it is working, why are you messing with the wiring? What exactly is the device in the ceiling?

Are there two switches controlling the light? If there are, then you most likely have a single hot (White re-tasked as an ungrounded conductor). This would be connected to the supply in the ceiling and run to the input on the switch. From the switch, a Black and Red would be fed back to the device or devices.

A picture would really help us, can you upload one for us, please.



First piroity, find the power source.

If the source is a separate cable then you have a switch loop.

On the 12/3 cable, what are colors of wires?

Chuck

The wires are black, white, and bare copper. The black and white are connected to either side of the switch. In the attack the wire is cut and the black wire is connected to the black source wire. The white wire is connected to the black wire on the light fixture. The white wire from the light fixture and the white source wire are connected. The ground wires are connected.

If it is working, why are you messing with the wiring? What exactly is the device in the ceiling?

Are there two switches controlling the light? If there are, then you most likely have a single hot (White re-tasked as an ungrounded conductor). This would be connected to the supply in the ceiling and run to the input on the switch. From the switch, a Black and Red would be fed back to the device or devices.

A picture would really help us, can you upload one for us, please.



First piroity, find the power source.

If the source is a separate cable then you have a switch loop.

Thanks for your answer, the source is just a light fixture. I was changing out the old switches with newer cleaner ones and this one just seemed wrong. It has one conduit coming in. The yellow cable with a black, white and bare copper wires. The black and white are connected to either side of the switch. But the light is working I was just wondering if I should be worried.