Replacing Electrical Switches - April 9th 2002
If a fuse blows or a circuit breaker trips every time you turn on a switch, the switch itself is probably to blame and should be replaced. There are many different types of switches, but replacement procedures for most of them are similar. You may wish to substitute a different type for the faulty one; for example, replacing an ordinary switch with a mercury (silent) type.
Make sure the electricity is turned off before beginning to work. Either remove the fuse or trip the breaker serving that circuit. Remove the two screws holding the cover plate and lift off the plate. Remove the mounting screws holding the switch to the wall box, and pull out the switch.
Carefully note the wiring of the switch. It will depend on where the switch is located with regard to the rest of the circuit. Wiring for a three-way switch (where a fixture can be controlled from two separate locations) is somewhat more complex, so make sure that the new switch is wired in the same way as the faulty one. If space permits, transfer one wire at a time from the old to the new so that you get them right.
Loosen the terminal screws and remove the wires from the faulty switch. Place the loops around screws on the new switch in such a way that they will be tightened when the screws are tightened. With needle-nose pliers, squeeze the loops closed around the screws. Tighten the screws firmly. Place the switch in the wall box, and install mounting screws. Replace the cover plate. Restore power to the circuit by replacing the fuse or turning on the circuit breaker, now check the operation of the switch.
Backwired switches are also available, and may be used as replacements for most ordinary switches. Installation is essentially the same as that described for backwired outlets.
Dimmer switches allow you to set the lighting mood of a room, from a soft, dramatic glow to dazzling brightness, and all ranges in between, simply by turning a knob. They also conserve electricity when set at a position other than full on. Installation in similar to other switches, except that the control knob is pressed on after the switch is mounted and the place re-installed.