There aren't many building components you can replace for about $7, yet that's all you'll pay for the simplest kind of switch--a single-pole model. All the more reason to replace the device when it's old and discolored, has been broken by someone moving a heavy piece of furniture or has just plain worn out. The swap takes only about 10 or 15 minutes. With a few specific tools, you can handle the job even if you've never done basic electrical work. Here's how it's done.
Light switch
Cut power and double-check that the circuit is dead using a non-contact voltage tester.
Remove old Switch
Loosen each terminal screw and remove the hooked wire from beneath the screwhead. Take off the switch and bend each wire out of the way. Vacuum out the box if it's dirty, and check that the electrical connectors are tight. If they're loose, replace them.
Clip and Strip
Check the ends of the wires for rough or nicked spots. Remember, wires expand and contract slightly with every use cycle, and can eventually fail at these stress points. Clip off the damaged area and carefully strip about 1/2 in. of insulation to expose pristine wire.
Bend a Hook
Insert the wire into one of the holes at the tip of an electrician's multitool, and bend the copper into a rounded hook.
Attach Wires
Position the switch so it's on when its lever is up. Attach the power wires to the brass terminal screws so the rounded hooks point clockwise. Attach a grounding wire to the green screw. The grounding-screw tab is delicate. Grip it with needle-nose pliers as you tighten the screw.
Install the New Switch
After the switch is wired, wrap electrical tape around its body and terminal screws to shield live electrical terminals. Screw the switch to the box and mount the cover plate over the switch--the job is done.
