Installing a Light Switch

 

 

In replacing a light switch, the type of switch must first be determined. The most common types are single pole, double pole, three-way, and four-way switches. A single-pole and double pole switch control from just one location while a three-way switch controls from two separate locations and a four-way light switch can control from three or more locations.

 Single Pole Switch

A single pole light switch will turn a light, appliance, or outlet on or off from one location. The surface of the switch will be marked with the words “on” and “off”. It has two terminals which are wired to the black (hot) wire. One terminal is used for the incoming hot wire and the other for the outgoing hot wire to the light, outlet, or appliance. The switches come either with a ground terminal or without.

 Double Pole Switch

A double pole light switch is similar to a single-pole switch since it also has the words “on” and “off” and can be used only in one location. Instead of having only two terminals, it has four, allowing it to carry two hot wires, controlling 240 Volt devices. The switch also comes with a ground terminal.

 Three-way Switch

A three-way light switch allows turning on or off a light, outlet, or appliance from two separate locations. They are always used in pairs. The switch has three terminals, one marked “com” with the dark screw for the black (hot) wire and the other two for the lead to the other switch. It doesn’t matter which of the two are used.

 Four-way Switch

The four-way switch is installed between two three-way switches for controlling a light fixture, outlet, or appliance from three different locations. The switch has 4 terminals as does the double pole switch, however, the four-way switch doesn’t have the “on” and “off” wording.

 

 How To Install A Light Switch

 
1. Turn off power

Never attempt replacing a light switch without first turning off the power at the circuit breaker or fuse box.

2. Remove switch cover plate

With a screwdriver, remove the cover plate retaining screws.

3. Remove light switch

Remove the two screws holding the switch to the switch box.

4. Disconnect the wires

Pull the light switch away from the switch box.  If the switch has more than two wires attached, either tag each wire with its location so they can be properly re-installed or immediately install each wire to the new switch as they are removed.

5. Attach wires

Most new switches have both a terminal screw and wire retaining port on the backside of the switch inline with the terminal screw.  The purpose of the wire port is for ease of wiring. If the wire port is used, remove the insulation from the wire, back three-eighths of an inch, and insert it into the hole until it bottoms out.  If you choose to wire to the terminal screw, remove three-quarters of an inch of insulation from the wire.  Now, make a small “u” shaped loop at the end of the wire.  Loosen the terminal screw to give enough slack for attaching the loop around the screw. Tighten the screw firmly.

6. Attach the switch to the switch box

Push the light switch completely into the box, carefully guiding the wires as you go.  Install the two retaining screws and tighten firmly.

7. Install cover plate