New Switches

The easiest switch to replace is the single-pole switch. Before popping in a new one—and this is true with any device—read the specifications on the old switch. These usually are listed on the metal mounting strap and include the following:

• The amperage and voltage ratings
• The type of current it will carry (AC only for house current)
• The type of wire that’s compatible with the device (CU for copper only, CO/ALR for copper or aluminum, ALR for aluminum only)
• Its Underwriters Laboratory or other testing service listing

The back of the device will indicate the acceptable wire gauge and a stripping gauge for measuring the amount of insulation to be removed prior to installation. The location of your switch will determine how its replacement gets wired. A switch can be at either the middle or the end of a run (one complete circuit). These positions in the run are simply defined:

• A middle-of-the-run switch can be anywhere between the beginning and the end of the circuit. There will be at least two cables entering the box (at a minimum, one on the line side coming from the panel and one leading to a fixture or other device).
• In an end-of-the-run switch (also referred to as a “switch loop”), the cable runs from the fixture to the switch. This requires special treatment of the white wire.

Remember to shut the power off at the service panel or fuse box and to test the switch with a voltage tester before removing the wires. Note the condition of the ends of the wires. You don’t want to reuse damaged or nicked wires. If you find any damage, cut off the minimum amount of wire necessary to remove this section and then strip off sufficient insulation (about 5/8 of an inch) so the wire will make a solid contact.