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. |
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).
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.