How to Use a Multimeter (AKA Multitester)

Continued from page 2

Testing for Ground

This test should be done when current is NOT present. Always unplug the device or turn off the main circuit breaker before attempting a ground fault test.

A ground fault test is done to determine if current is passing from a circuit inappropriately. A ground fault is a potentially dangerous electrical shock hazard. A ground fault can also cause a device to malfunction.

Set the multimeter to the ohm setting. If there is more than one ohm setting, choose X1. Touch one probe to a terminal and touch the other probe to the device's housing or mounting bracket. Now move the first probe to another terminal. If the multimeter displays anything other than a reading of infinity for any of the test combinations, a ground fault exists and the device should be repaired or replaced. Do not use a component that has a ground fault.

Measuring Resistance

This test should be done when current is NOT present. Always unplug the device or turn off the main circuit breaker before attempting to measure resistance.

Resistance is how much the flow of current in a circuit is impeded. Resistance is necessary for heat to be generated in heating elements like those used in an electric stove or oven, dryer or hair dryer.

It is necessary to know what the proper resistance rating should be for a particular device in order to determine if it is functioning properly.

Set the multimeter to the ohm setting. Touch a probe to each of the terminals. The reading on the multimeter should change from infinity to the level of resistance detected in the element. Compare the measurement to the manufacturer's specification for the element.

page 3 of 3