Safely Wiring a Light Switch: Red and Black

The problem with electrical DIY projects is that there usually isn’t any room for error. Incorrect wiring can cause injury and shock, and sometimes a house fire. But safely wiring a light switch of the single pole variety is a simple project if you proceed carefully.

First Steps

First, turn off the power at the breaker panel. This is a critical step to prevent electrocution.

Once the breaker is off, remove the switch plate from the electrical box surrounding the switch.

Testing

Use a multimeter or current tester to make sure every wire in the electrical box.

Documenting

Grab your phone and take a picture of how your old switch is wired. This is because wiring can vary in homes of different ages.

Remove the old switch

Using a screwdriver with a rubber handle, remove the screws holding the switch in the electrical box.

Disengage the old switch

Your switch is wired with three wires: a black or red wire, a white wire, and a green or copper wire.

Red and black wires are live or “hot,” and carry electricity. These are attached to the switch device with a brass screw.

The white wire is neutral and often carries electricity. This one is attached to a silver or light-colored screw.

The green or copper wire is the grounding wire and attaches to a green screw.

Detach the wires from the switch with the screwdriver.

Preparing the wires

Trim any frayed wire ends and remove the insulation up to half an inch with a wire stripper. Bend the wires into a hook with a pair of pliers.

Connecting the new switch

Unbox your new switch and find where the top is marked on it and note the placement of the screws. Now, take a look at the picture you took earlier for reference.

Wrap the black or red (live) wire around one of the brass screws, going clockwise. This ensures the wire connection will be tightened when the screw is turned.

Likewise, connect the white wire to the neutral terminal (or silver) screw. Then connect the copper or green wire to the green, grounding terminal screw.

Tighten all with the screwdriver to ensure connection.

Mounting

Place the new switch back into the box. If the electrical box is plastic, you can simply shove the excess wire back into the box.

If you have a metal electrical box, wrap exposed wire with electrical tape to prevent it from contacting the box.

Ensuring that you have the switch right-way up, use the new screws that came with your switch to secure it in place in the box.

Replace the switch plate with the original screws.

Complicated Wiring

Three-way light switches may prove too complicated for the new DIY homeowner. Also, older homes with metal boxes and no grounding system may require a professional.