Timer switches are designed to turn an electrical device on or off at specific times, to automate the times when the device is in use. Commonly used with landscape lighting and sprinkler systems, electrical timers can often replace single-pole switches. In some cases, a timer switch may require installation where only the hot leads are switched. You can replace a single-pole switch with a timer switch with no neutral connection based on the timer's wiring diagram in a few minutes with some basic hand tools.
Turn off the breaker to the electrical circuit to which the timer switch will be connected at the breaker panel.
Loosen the plate cover screws with a screwdriver and remove the plate cover over the existing switch. Hold the tip of a noncontact electrical tester against the wires connected to the switch. If the light on the tester illuminates, turn off more breakers or the main breaker to the electrical panel, and retest until the tester light no longer comes on.
Loosen the mounting screws and pull the switch out of the switch box. Loosen and remove the screws on the wiring terminals, and pull the wires off of the terminals. Set the switch aside.
Clip off the bare wire loops on the ends of the wires in the switch box with the cutting tip of a pair of wire strippers. Then strip 1/2-inch of insulation from the tips of the wires.
Connect the black lead wire from the electrical panel to the hot wire on the switch (typically a black wire) with a wire nut. Consult your timer's wiring diagram to ensure which wire is the hot lead from the switch. Then connect the switched wire (typically a blue wire) to the black wire leading to the device. Finally, connect the green wire from the switch to the bare wire in the switch box.
Push the wires into the switch box and mount the switch box with the two mounting screws. Place the switch cover over the switch and tighten the screws to mount the cover.
Turn on the power to the switch, and set the timer to manual mode to test the operation of the device. If it tests properly in manual mode, set the timer as per the operating instructions for the switch.
Things You Will Need
- Noncontact electrical tester
- Timer switch
- Wire stripper
- Wire nuts
- Do not attempt to begin wiring without first verifying with a noncontact electrical tester that the power is off to the electrical circuit.
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