If you’re testing for continuity in home electrical wiring, turn off the appropriate breaker at your main electrical service panel. Next, test a non-contact voltage tester on a circuit you know is working (such as any meter you use daily). Then, use the non-contact voltage tester to make sure the power is off at the circuit you’ll be testing. [1] X Research source Separate the circuit you want to test from other potentially hot wires to ensure you don’t get a false positive. Then, simply place the tip of the voltage tester near the wiring of the circuit you’ll be testing. If the voltage tester lights up and “chirps,” the power is still on.
To test that it’s working, simply touch the clip to the probe. If the lamp comes on, it’s working. If it doesn’t, check the battery. Continuity testers are cheap and easy to use, but you can also find instructions online for making your own with a few simple parts.
If you’re trying to figure out which wire connects to which between a wall switch and nearby wall outlet at home, take the cover plates off and unbundle or detach the wire ends—but only after you’ve confirmed with a voltage tester that the power is off. Attach the tester’s clip to a wire at one box, then start touching the probe to wires in the other box. [4] X Research source
Non-contact voltage testers look like thick pens and can be found at any hardware store. They light up and make a chirping sound whenever the probe end is placed in close proximity to an electrical current. When using a non-contact circuit tester, make sure to separate the wires you want to test from all nearby wires. If the wires are too close, a hot wire’s magnetic field can affect the reading and show a false positive.
Typically, the symbol will look something like this— ))))) —except that the curved lines will go from smaller to larger from left to right. Read the manual that came with your meter before using it to ensure you know how to use it correctly.
Plug the black test lead into the “COM” (or similar, for “common”) jack. This is always where the black lead goes, no matter the test you’re conducting. Plug the red test lead into the jack labeled “VΩ,” “VΩmA,” or similar. [7] X Research source This jack is used for low current testing, which is appropriate for circuit continuity testing. Consult your multimeter’s manual if you’re not sure which jack to use. [8] X Research source
If your multimeter doesn’t beep, and the digital display (if it has one) shows “OL” (for “open loop”) or the number 1, then it is not working properly. Check its battery and consult your user’s manual.
Remember that, in most cases, a beeping sound and possibly a displayed “0” indicate continuity, and no beeping and possibly a “1” or “OL” indicate discontinuity.
If you don’t have knowledge or experience working with electricity, this task is best left to a certified electrician. You can buy circuit testers at any hardware store, and they look a bit like a continuity tester—a small cylinder with a light at one end (neon in this case) and two attached wires with probes (instead of one). Circuit testers are not-self powered, though, meaning that, unlike a continuity tester or multimeter, the circuit you’re testing needs to be supplied with power.
Another way to confirm the power is off is to plug a device (that you know is working properly) into the outlet.
Live, exposed wires create a hazard for electrocution (if someone touches the wires) or fire (if the wires touch each other or a nearby object). Before turning the power on, make sure the exposed wire tips are completely separated and not touching anything; tell everyone in the area/home that there are live wires in that specific location; and put up a sign (e. g. “Live Wires! Don’t Touch!”) right near the outlet.
You’re testing the tester by completing this circuit. If the neon lamp doesn’t light up, either your tester is bad or the power isn’t actually back on to your outlet.
If the neon lamp doesn’t light up, the ground wire in this outlet box is not properly connected to the home grounding system. Call an electrician if you are not well-versed in making home electrical repairs. After a successful test, turn the power off at the breaker box; test the exposed wires with the voltage tester to be sure the power is off; reconnect the wires as before and close up the outlet box; and turn the power back on at the breaker box.
