Electricity can kill, so it is very important to be careful while working with it and to use safety equipment. If you are not competent working around electricity have an electrician do the work.

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Three-way switches can be a little confusing because, unlike a standard switch, they have three screw terminals and do not have ON-OFF markings. Three-way switches are always installed in pairs and are used to control a set of lights from two separate locations.

One of the screw terminals is darker than the others. This is the common screw terminal. Before disconnecting a three-way switch, always label the wire that is connected to the common screw terminal. It must be reconnected to the common screw terminal on the new switch.

The two lighter-colored screw terminals are called the traveler screw terminals. They are interchangeable so there is no need to label the wires attached to them.

2 Steps

1. Safety alert: always turn off power at the main service panel before attempting switch repairs or replacement. Connect the common wire to the dark common screw terminal on the new switch. On most three-way switches, the common screw terminal is copper (or it may be labeled with the word COMMON stamped on the back of the switch).

2. Connect the remaining wires to the brass or silver "traveler" terminals. These wires can be connected to either screw terminal. Carefully tuck the wires into the box. Remount the switch, and attach the cover plate. Restore the power at the main service panel.