Key to wiring diagrams

Black wires are HOTBlack wires (HOT)
White wires are neutralWhite wires (NEUTRAL)
Red wire are travellers or switchRed wires (TRAVELLER or SWITCH)
Green wires are groundGreen wires (GROUND)
White wires marked as being HOTFor ease of illustration, white wires marked with a black circle are HOT not NEUTRAL. In real life these wires would normally be marked with black tape
two wire cable with ground2 wire cable with ground - the ground is shown as green for illustration but is actually a bare copper wire
3 wire cable with ground3 wire cable with ground - the ground is shown as green for illustration but is actually a bare copper wire

Switch box - metal type with ground terminalSwitch box - used to mount 2, 3 and 4 way switches
Octagon box - used for light fixturesOctagon box - used to mount light fixtures
Light fixture - showing lamp with hot and neutral terminalsLight fixture - showing lamp, hot and neutral terminals
2 way switchTwo way switch >>MORE INFO
3 way switchThree way switch - used to control a light from two locations >>MORE INFO
4 way switchFour way or crossover switch - used, in conjunction with three way switches, to control a light from three or more locations>> MORE INFO

  • Michael Schaffter

    The three way switch with power coming in at switch diagram is wrong! Once you disconnect the hot black wire coming from the wall all power going to the circuit is cut off. You disconnect from that when you switch from up to down. The ports on the left side of the switch rotate back and forth, but the red wire port is always connected. The ports on the three way switches which connects to both poles of the switch is on the right which is connected to the red wires. The correct way to wire the switch is to cut the red wire at the light fixture location and connect both ends of the cut red wire to the two connections at the light fixture.