When nothing is hooked up there is power in the 2 wire plus ground cable on the upstairs switch. This 3 way switch wiring diagram shows how to wire the switches and the light when the power is coming to the light switch.
Insteon 3 Way Switch Alternate Wiring Bithead S Blog
3 way switch wiring power at switch. The two switches appear to be connected by a 3 wire plus ground cable. Regardless of what 3 way switch wiring diagram youre following youll need to use a 3 wire cable to connect the two 3 way light switches. The key to wiring 3 way switches the power feed and the switch leg leading to the fixture s typically one at each switch location are attached to the screw terminal found at one end of the switch by itself. Then a 4 wire cable going between the two 3 way switches and then a 3 wire cable going from the switches to the load. In the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box. Traveler wires are interchangeable on each switch.
Each 3 way switch in these examples are controlling the power source to the same load. The black line wire connects to the common terminal of the first 3 way switch. So what you should see if you have correct 3 wire electrical cable romex is a black power white neutral and now a 3rd red wire. In this diagram the incoming hot wire attaches to the first switchs common dark colored terminal. This terminal is usually identified by a darker colored screw. When wiring a 3 way switch circuit we will be using a 3 wire cable known as romex coming from the source such as the breaker box.
A 3 wire nm connects the traveler terminals of the first and second 3 way switch together. The two hot wires of three wire cable connect to a pair of brass colored traveler terminals on each switch. There is only the single 3 wire plus ground in the downstairs switch box and only two 2 wire plus ground cables at the fixture. Typical 3 way switch wiring nm cable.
Gallery of 3 Way Switch Wiring Power At Switch
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