On A Light Switch What Is The Red Wire. Except in rare cases, it is a hot wire or a switched hot wire. Or it could be the red wire is the wire going to the fixture, and the black wires are the live wires.
In the picture the two wires to the left are the hot wires, and the two black wires to the right lead The red was most likely on the other screw of the switch and is a 'switched hot' feeding a light or receptacle. The way a light switch is wired depends on whether the power comes into the light box or the switch box first. But first, let's get my disclaimer.
Flipping the switch interrupts the flow of electricity to.
The protective ground wire (listed as green-yellow) is green with yellow stripe.
Use your voltage twister to check that there isn't a current running through the screws. If you have wall switches that are old and badly faded, cracked, or just worn out and ugly, then replace them with brand-new switches. When you turn on a light switch, power goes to the light through the "hot" (black) wire and then back through the neutral (white) wire to the ground.