Switches
and outlets are essential in modern living. They are not indestructible,
though they sometimes seem that way. When you must replace one or
the other, the task is fairly simple. Always follow established
safety procedures; be sure the current in the circuit is shut off
at the service panel, and double-check with a voltage tester. Do
not work in a wet or damp environment. Always practice safety as
you work.
SWITCHES:
A switch controls the flow of power in an electrical circuit. When
the switch is on, electricity flows through the circuit from its
source to a point of use. Most residential electrical switches are
one of several toggle (or snap) types. To determine the exact type,
turn off the circuit to the switch before you begin. Then remove
the faceplate and the mounting strap screws to release the switch.
Pull it out toward you. The switch will be attached to the cable
wires by either screw terminals or, less often, spring clamps like
those in back-wired outlets. Most commonly, they have both side
terminals and back-wiring holes. The number of connections tell
you which of the following types of toggle switches you have.
Single-Pole
Switch-
A switch with two terminals is called a single-pole switch; it alone
controls the circuit. The incoming hot wire is hooked to one terminal
screw, and the outgoing hot wire is connected to the other screw.
Three-way
Switch-
A switch with three terminal screws is called a three-way switch.
One terminal is marked COM, or "common"; the hot wire is connected
to this terminal. The other terminals are switch leads. Two three-way
switches are used to control a circuit from two places.
Double-Pole
and Four-Way Switches-
A double-pole switch has four terminals. It is normally used to
control 240-volt appliances. A four-way switch also has four terminals.
Three four-way switches are used in a circuit to control one outlet
or fixture from three separate places. Both switches look the same,
but a double-pole switch has ON/OFF markings.
In addition
to the terminals mentioned, most switches will have a green terminal
for a ground wire.
POSITIONS
OF TERMINAL SCREWS:
The position of terminal screws varies to let you select a switch
that permits the most convenient placement of wires in the switch
box. No matter which switch you select, it will fit into a standard-size
box.
Side-Wired
Switch-
This type of terminal arrangement has screws on one side of a single-pole
switch or on both sides of three-and four-way switches.
End-Wired
Switch-
Another type has screws on the top and bottom of the switch housing
with screw heads pointing up and down, respectively.
Front-Wired
Switch-
A third type of terminal arrangement has screws facing the front
of the switch, with one screw at the top of the switch and the other
at the bottom of the switch. This type is very rare.
Back-Wired
Switch-
This type doesn't have terminal screws. It has holes in the rear
of the switch into which wires are pushed. Below each hole is a
slot. To release a conductor, use the end of a paper clip, screwdriver,
or similar tool to press the tang in the slot. To insert a conductor,
press the tang in the slot and insert the wire. The wiresmust be
perfectly straight and exactly the length indicated on the side
of the device.
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