A non-contact voltmeter can help you quickly check for the presence of live wiring without touching bare metal. While a standard voltmeter can give you a precise measurement of voltage in a circuit, you must touch the meter's probe to the circuit to do it. A non-contact meter will signal you if a wire has voltage in it greater than a certain level, but it will not give an exact reading.

How to Use Non-Contact Volt Meters?

1. • 1

     Plug a table lamp into an electrical outlet, and turn it on.

   • 2

     Turn the voltmeter on. If the voltmeter is a multifuction meter, turn its non-contact voltmeter mode on. Hold it to within 1 inch of the lamp's electrical cord. The voltmeter should give a clear indication of the presence of voltage. It may flash a light, make a beeping sound or both. If it does not, check the meter's battery and replace it if necessary. Try the test again.

   • 3

   • Turn the lamp off. Move the meter back and forth over the lamp cord. It should still give a voltage reading, since the lamp is plugged in.

   • 4

     Unplug the lamp. Hold the meter near the lamp cord. It should not indicate a voltage.

   • 5

     Hold the meter next to the outlet. It should indicate a voltage.

Tips & Warnings

• Some non-contact voltmeters are sensitive enough to detect voltages as low as 24 volts. This is handy for tracing low-voltage wiring such as doorbell circuits (Reference 2, page 17).
• Metal conduit, shielding, outlet boxes and panels will interfere with the meter's ability to detect a voltage.