How to Test a Light Switch and Outlet

Testing Light Switches and Outlets using Neon Bulb Testers

By Mark J. Donovan




If you have plans to work on an electrical light switch or outlet it is important to test the light switch or outlet first to make sure power is off. To test a light switch or outlet you need a neon bulb circuit tester or a Tick-tracer circuit tester.

Neon circuit testers and Tick-tracer circuit testers consist of a neon bulb and leads that allow you to check if a light switch or outlet is powered on. When you press the leads into either an electrical outlet or on the light switch terminal screws the neon bulb will light up if the outlet or light switch has power feeding to it.

If the neon bulb does not light up, power is off at the outlet or switch and it is safe to work on.

Before working on a light switch, outlet or any other electrical circuit or appliance in your home, first turn power off to the circuit at the main circuit breaker box.

Before testing a light switch or outlet for power, check the neon bulb tester or Tick-tracer circuit tester on a known powered outlet to confirm that the neon bulb does indeed turn on. Once you have confirmed that the neon tester works properly, you can then use it to test a light switch or outlet.

Testing a Light Switch

When using a neon circuit tester on a light switch, apply one lead probe to the bare copper ground wire attached to the light switch and the other lead probe to each terminal screw.

High Voltage AC Circuit Tester

For each terminal screw, confirm that the neon tester does not light up. If the neon tester does not light up in any of the tests, then the light switch is safe to work on.

If in the event the light switch does not have a bare copper ground wire attached to it, then use a Tick-tracer circuit tester to test the light switch.

Place the Tick-tracer circuit tester lead probe on each terminal screw of the light switch and confirm that the bulb does not light up.

Testing an Electrical Outlet

When using a neon circuit tester on an outlet, insert one lead into one of the outlet socket openings and the other into the ground socket opening. While keeping the one lead in the ground socket opening, move the other lead to the other socket opening. If the neon bulb does not light up in either case, power is indeed off to the electrical outlet.

If testing an outlet with a Tick-tracer circuit tester, insert the lead probe into each of the socket openings and confirm that the neon bulb does not light up.


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