Why would a light switch suddenly stopped working

Why would a light switch suddenly stopped working

Most wall switches in your home control lighting fixtures, but they may also control electrical outlets or hard-wired appliances, such as your garbage disposal. As these switches are used frequently (e.g., a light that is turned on and off several times a day), they tend to wear out. However, a mechanical failure of the switch itself is not always the reason a light does not work. A switch is just one element in a complex circuit that starts at the electrical panel, runs through the wires in the wall to the light switch, and then runs through other wires to the light, socket or fixture. If a light switch is "faulty," the problem may be somewhere in the circuit from the switch to the light.

Therefore, troubleshooting a faulty light switch involves, at least in part, examining the entire circuit to determine where the problem actually lies. If other possibilities have been ruled out, the last step is to replace the light switch.

Troubleshooting wall switches

If your wall switch is no longer properly operating the light, outlet or appliance it's supposed to control, it's time to follow these simple steps to find out what the problem is. Remember that your investigation may reveal problems that are not related to the switch.

Before you begin

There are many styles of wall switches, but beyond the aesthetic differences between simple toggle switches, push buttons, slide switches and dimmers, there is a more basic technical difference. There are single-pole switches that can be controlled from a single location, three-pole switches that can control lights or outlets from two locations, and, for larger homes or complex situations, four-pole switches can be used to control lights or outlets from three or more locations. If, in the course of troubleshooting, you discover a mechanical problem with your switch, find out what type of switch you have before purchasing and installing a replacement.

What you need

Hardware tools

Non-contact circuit tester

Screwdriver

Continuity tester

Torch

Materials

Cable sockets (if required)

New wall switch (if needed)

Instructions

Checking the switch

Sometimes a damaged or defective switch is immediately visible. If the switch or switch slide mechanism is loose or not functioning properly, it is likely that the mechanical parts inside the switch are simply worn out. If the switch emits a buzzing sound, is hot to the touch, or shows signs of burning or melting, it is almost certainly defective and should be replaced immediately.

Hand-painted warm light switch

Warning

If the switch emits an audible buzzing sound or appears to be hot, it should be turned off and repaired immediately. Such a switch may pose a fire hazard and should be replaced as soon as possible.

Check the bulb or socket.

If there is no obvious damage or problem with the circuit breaker, rule out a few simple things first: make sure the light bulb is not burned out or that the light or appliance connected to the socket controlled by the circuit breaker is working properly.... If the problem is simply a blown bulb, there is no point in taking the time to replace the wall switch.

Replace the bulb in the ceiling.

Check the circuit breaker; turn off the power.

A faulty circuit breaker may simply be a tripped breaker or a blown fuse. Go to the electrical panel and locate the circuit breaker or fuse. If the circuit breaker has tripped, reset it, or if the fuse has blown, replace it with an identical one.

If resetting the circuit breaker or replacing the fuse does not solve the problem, check the circuit breaker wiring and connections more carefully. Before doing so, disconnect the circuit by turning off the circuit breaker or removing the fuse.

Tips

If the circuit breaker trips every time the wall switch is turned on, there is most likely a short circuit somewhere in the wiring. A short circuit occurs when a loose or damaged wire causes the current to deviate from the established circuit. If the problem is somewhere other than the circuit breaker itself, fixing the short may be the job of a licensed electrician.

Point your finger at the tripped circuit breaker on the control panel.

Remove the cover plate and check the power supply.

Carefully unscrew the cover plate from the wall, remove the cover plate and check the circuit breaker. Using a non-contact neon circuit tester, make sure that the wires connected to the circuit breaker are not conducting electricity. Passing the probe near the wires or screw terminals of the circuit breaker will illuminate if voltage is present. Never touch any wires until you are sure that there is no voltage.

Checking wire connections

In many cases, circuit breakers do not function properly because the electrical connections, either the circuit connections in the circuit breaker box or the wires to the breaker itself, have loosened, preventing the current from following its intended path.

Using a torch, inspect the inside of the breaker box and check the quality of the wire connections. This may involve loosening the screws holding the circuit breaker in place and removing it from the breaker box.

If you find a bad wire connection, you can fix the problem by simply reconnecting the wire to the circuit breaker. If you find that the circuit connections inside the box are loose, secure them with wire connectors.

Once you have repaired the loose wire connections, you can put the breaker back in the control box, replace the cover plate, reconnect the circuit and check that the breaker is working properly. If the problem persists, reconnect the circuit and be prepared to remove and test the circuit breaker (next step).

Tips

Although less common, problems with the wire connections on the lamp itself can sometimes cause problems. Even if the switch and its connections appear to be intact, it is a good idea to check the wiring connections to the lamp circuit.

Disassembling the switch

If the problem persists after following the first step, remove the switch from the control box (only after making sure the power is off) and disconnect the switch from its wiring. It is usually sufficient to loosen the screws connecting the wires. Some switches may be connected to the circuit wires via snaps, in which case you will need to insert a small nail or screwdriver into the release slot to loosen the wires.

Continuity test

Use a battery-powered continuity tester to check the switch mechanism. This is a simple test where the tester's test leads are clamped to the screw terminals and the switch lever is rotated back and forth. A small LED will light up when the switch mechanism has successfully completed its travel between the test leads. If the test shows no continuity, the switch is defective.

If the switch is defective, installing a new wall switch is a simple project.