A three-way switch allows you to control your lights from two different locations. Did I say two locations? Yes, you heard right because you can turn the lights on or off from any of the two locations. The three-way has four screw terminals. Two brass terminals for the travelers. One black terminal for the common, and a green terminal for the ground.
what is a three-way switch used for
Ways in where you would use a three-way are when you have a staircase between floors. Another place you would use a three-way is if you have long railroad rooms, a kitchen, or a hallway. Above all, If you have a staircase to your home that leads to an outside door. This will come in handy if you forget to turn the light off when leaving the house.
how does a three-way switch work
A three-way works by transferring power from one side of the device to the other. . It is almost like a relay with an open and closed circuit. When you flick the switch up the circuit opens and the light turns off. When you flick the device down the circuit closes and the light turns on. It is important when wiring a three-way to make sure that your travelers are on the correct terminals on the switch. After wiring your three-way switches test them out. Ture the lights on with one of the switches. Then try to turn the lights off with the other switch. Then go back to the first switch and turn the lights on. Now try to turn the lights off with that same switch.
If the lights stay on that means that your travelers are crossed. If you follow the aforementioned procedure you will save time spent and possibly money down the road.