How to Test an Outlet With a Multimeter

The all-important electricians tool: the multimeter

Testing an unknown electrical outlet with a multimeter is a wise thing to do before plugging an appliance into an unknown power source. As voltage varies in electrical outlets in homes, some larger for ovens and clothing dryers, it is important to check unknown ones before using them. With a simple digital or analogue multimeter you can remove any doubt and ensure you use the proper appliance in the proper outlet.

Things You'll Need

• Multimeter

Instructions

1. Turn the dial on the face of your multimeter to select AC voltage. Electricity in homes is almost always supplied in the form of alternating current (AC) as opposed to direct current (DC) and will be indicated by a 'V' followed by a sine wave (~). Set it to the highest number in this range.

2. Insert the tip of the black negative probe lead from the meter into one of the two vertical slots in the power outlet.

3. Insert the tip of the red positive probe lead into the other of the two vertical slots in the power outlet.

4. Turn the selector wheel on the multimeter down from the highest AC Voltage rating until you get a clear reading. Most common outlets in North America supply between 110 and 120 volts AC, while outlets designed for stoves or other large appliances may supply between 220 and 240 volts AC. If no reading is received, there is no power flowing to the outlet.

Tips & Warnings

• Always check a known working power outlet to ensure your meter is performing correctly before checking unknown outlets.

References

• Ladyada: Multimeter Tutorial