The other terminal is for a second hot wire called a switch leg that runs only between the switch and the light fixture. With three ways switches or four way switches like opposite ends of a hallway to turn on or turn off the smae light from two different places we use yellow or orange wires for travelers one three way has the hot wire hooked to it and either one traveler for three ways or two for four ways to act as the hot wire.

Light Switch Wiring Diagrams Do It Yourself Help Com
2 hot wires light switch. Wires 2 3 were wirenutted together with a short piece of wire as a pigtail and the pigtail was connected to the other screw on the switch. Wire 2 is constant hot. Run 12 gauge electrical cable between each switch and the light it controls. With the switch removed wire 1 is constant hot. U connects to the light and is the common terminal. The ground screw is for the circuit ground wire connection.
Connect the 2 ground wires with a fourth wire nut. Wire 1 is connected to one of the screws on the switch. Pull one end of each cable through the back of one of the light fixture electrical boxes. This is an updated version of the first arrangement. Install a double switch wall box and run the feed cable. The red and black are used for hot and the white neutral wire at the switch box allows for powering a timer remote control or other programmable switch.
Standard single pole switches do not connect to neutral circuit wire. One switch the common terminal will be hot only in the switch position where the light is on. Connect it to the screw on the left side of the switch. Shut off the power to the circuit. Take the white wire leading to the second box and mark its end black too. The switch leg brings power to the fixture when the switch is turned on.
Begin by installing the feed cable from the power. Strip both ends of each cable. How to wire two light switches with one power supply step 1. Use a circuit tester to verify that the power is off to the circuit you are. Because the electrical code as of the 2011 nec update requires a neutral wire in most new switch boxes a 3 wire cable runs between the light and switch. Connect the red wire leading to the second switch to the top brass screw on the right side.
Wire 3 is not hot. Or more simply if the switches work at one switch the common terminal will be hot in either switch position. That is the hot feed wire. There are 3 black wires in the switch box that is supposed to control a light fixture. Switch and t is hot and the light went out.