What is 3 12 wiring?

Answer 1

Traditionally in electircal wiring 12/3 would refer to the size or diameter of the wire being used. In this case it would be 12 gauge which in laymans terms is about the size of a thick pencil lead. The number 3 would indicate how many lead wires are available to be used to run current on them. Additionally to this there would always in any wire with this type of description has a ground wire in it which is not counted. So in fact there is 4 Four total wires in the casing. One White (Neutral - sends current back to the service panel) One Black (Hot - provides 110v of power) One Red (additional wire to run 110v or to run power to a light from a switch so you can turn the light on from two different ends of a room or staircase). One uncoated copper wire Ground (sometimes if it is coated it would be in green).

The purpose of this type of wire as it refers to the 3 is that it gives you an extra wire to run to a switch or a seperate plug or to run two 110v wires inside the same casing to meet code on wiring 1 phase 220v wiring.

In the case of wiring what they call a three-way light switch the power comes into the first switch and sent to the light, the red wire sends power from the first switch to the second switch, then the white is all connected for neutral. Without the Red wire sending power to the second switch the first switch would just simple turn off the power to the second switch and render it useless. Ever play switch tag to turn one on and leave it on so the other one works. Yeah that thing.