How to Properly Test Light Switches

Use a robust insulation resistance tester to check whether light switches are connected correctly.


- Once the light installation work is finished, check the insulation state of the light line before turning on the light.
- Check the line from the light switch to the light for proper insulation in order to prevent fire hazards.

* Turn off the ampere breaker and the circuit breaker for the light line.
* Connect the insulation resistance tester to the circuit breaker.
* Output an appropriate test voltage (which varies depending on the supply voltage).
* Check that the insulation state is good at the time the light switch is off.
* Turn on the light switch and check that the resistance value approaches zero (by the load resistance of the light).
* A low resistance value at the time the light switch is OFF indicates an insulation failure. The likely cause is a connection failure.
* A high resistance value at the time the light switch is ON indicates the possibility of a connection failure.

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