In the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box. The second wire is connected to the common terminal or black screw of the second 3 way switch and its destination is the corresponding terminal of the bulb black. The first way of wiring uses a couple of two way light switches with a 3 wire control. Three wire cable runs between the switches and 2 wire cable runs to the light. That is because that wire is the switch leg going to the light. This method is depicted in the diagram at the top of this post. I have access to the light s wiring and can add the switch easily there. I don t want to rip up the drywall though to put a 3 wire cable in. You can observe in the schematic that both the com terminals are connected together. I think that the most common method used to wire a set of 3 way switches is to bring the two wire line cable into one switch box and bring the two wire load cable into the other switch box.

Wiring diagram 3 way switch with light at the end in this diagram the electrical source is at the first switch and the light is located at the end of the circuit. The black line wire connects to the common terminal of the first 3 way switch. I want to add a switch downstairs. A three conductor cable with a ground is then installed between the two 3 way switch boxes. I must assume that the three wires are all in the same cable. The third wire is connected between one of the traveler terminals of the two 3 way switches. 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. This is the 3 wire cable which you must have to wire a 3 way light switch. I have access to the light s wiring and can add the switch easily there. I ve got a light downstairs with the switch upstairs.

I must assume that the three wires are all in the same cable. Run the traveler 2 wire through the same holes as the receptacle feeder 2 wire instead of alone across the attic. I have access to the light s wiring and can add the switch easily there. Therefore one of the black wires is actually a white wire colored black. The black line wire connects to the common terminal of the first 3 way switch. This is the 3 wire cable which you must have to wire a 3 way light switch. So the proper wiring would be red and black on the brass colored terminals and the white wire colored black would go on the dark terminal. I don t want to rip up the drywall though to put a 3 wire cable in. The black and red wires between sw1 and sw2 are connected to the traveler terminals. Three wire cable runs between the switches and 2 wire cable runs to the light.

That is because that wire is the switch leg going to the light. Typical 3 way switch wiring nm cable. I want to add a switch downstairs. You can observe in the schematic that both the com terminals are connected together. Try to keep the 2 wire traveler cable bundled close to the cable with the hot and neutral. The second wire is connected to the common terminal or black screw of the second 3 way switch and its destination is the corresponding terminal of the bulb black. Red wire traveler or switch wire. I have access to the light s wiring and can add the switch easily there. In the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box. The black and red wires between sw1 and sw2 are connected to the traveler terminals.

I want to add a switch downstairs. That is because that wire is the switch leg going to the light. In the 1st diagram below a 2 wire nm cable supplies power from the panel to the first switch box. Regardless of what 3 way switch wiring diagram you re following you ll need to use a 3 wire cable to connect the two 3 way light switches. Red wire traveler or switch wire. Wiring diagram 3 way switch with light at the end in this diagram the electrical source is at the first switch and the light is located at the end of the circuit. The black and red wires between sw1 and sw2 are connected to the traveler terminals. The black line wire connects to the common terminal of the first 3 way switch. Traveler wires are interchangeable on each switch. The second wire is connected to the common terminal or black screw of the second 3 way switch and its destination is the corresponding terminal of the bulb black.