How a light switch is wired (one-way)
We must first locate a one-way light switch. The circuit may be quickly rejected as a single switch circuit if you are aware that a light can be operated from two places (for example, one light switch positioned at the bottom of a stairway and another located at the top of the steps).
Setting Up
A switch has to be replaced and rewired if it has failed. There are normally two types of modern switches. There are switches that need a screw to hold the wire in place, and there are "plug-in" type switches that use a spring push-button release mechanism. We advise utilizing switch plates with screws for greater dependability.
STEP 1: Disconnect the power
Determining which lighting circuit the new switch will be placed on and turning off the power source should come first. In more contemporary houses, an MCB (miniature circuit breaker) is found in the mains consumer unit to do this. You may decide to locate the right fuse at the fuse panel after business hours in bigger buildings like office buildings or schools where the brief interruption of mains electricity is likely to annoy a lot of people. Use a voltage tester to check that the circuit is not active and that the switch is not receiving power for further safety.
Remove the Current Switch Plate in Step 2
Remove the switch plate's screws, carefully pull it toward you, then count and identify the wires' color. (Hint: The plate will be fastened to three wires maximum. If you are aware that the light switch was working properly before you replaced the switch plate, all you need to do is make a note of the wires' arrangement and reproduce it on the new switch plate.)
Always check the wires with a voltage tester to make sure there is no mains supply before beginning to detach them, just in case.
Determine the wires and wire ports in STEP 3
If there isn't an existing light switch from which to copy the wiring arrangement, we must determine which wire goes into which port based on the color of the wires and the labels that are placed next to each wire port on the back of the switch plate.
Wiring the Switch Plate (STEP 4)
Next, locate the wire connections marked "Common" and "L1" on the rear of the new or replacement switch plate (an additional L2 port may be found next to the L1 port on some units intended to be used as a single switch - the L2 port is used in wiring two-way circuits and may be ignored when wiring a one-way circuit).
Connect SW (blue) to the L1 port.
Connect CW (brown) to the Common port.
Connect the Earth wire to the Earth connections found on the switch plate and back box*
Only metal switch plates and metal back boxes include earth terminals (i.e. Earth terminals are not found on plastic switch plates and plastic back boxes).
The Earth wire may be terminated within the protective insulation sleeve of the wire and folded over when using a plastic switch plate and plastic back box.
Connect the Earth wire to the Earth wire termination if the switch plate or back box is constructed of metal.
The Earth wire should be connected to the Earth terminal in the metal back box first, and then an additional piece of wire should be used to connect the Earth terminal on the metal switch plate to the Earth terminal on the metal back box if BOTH the back box and the switch plate are metal.
