Electrical Testers and Their Uses

Electrician technician at work on a residential electric system.
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  • 01 of 07

    Do You Need an Electrical Tester?

    Electricians use a variety of testers to check a wide range of electrical properties, but as a homeowner, you might wonder, "What does an electrical tester do?"

    First of all, there are many different types of electrical testers and many possible tests. Electrical testers are used to check both AC and DC voltage and amperage as well as basic circuit characteristics like continuity, ​shorts and open circuits, and polarity, among others. If you don't know what those are, don't worry. The most important tester for any DIY electrical work is a voltage tester, and there are several testers that can check for voltage. 

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  • 02 of 07

    Inductance Testers

    Inductance Testers

    Inductance testers, better known as non-contact voltage testers, are probably the safest testers around, and they're certainly the easiest to use. They allow you to check for voltage in wires or devices without you having to touch any live parts. The device is like a mini wand with a small tip on the end that senses voltage in such things as electrical wiring, outlets, circuit breakers, lamp cords, light sockets, and switches. You can get a reading simply by sticking the tip of the tester into an outlet slot or even touching the outside of a wire or electrical cable.

    Inductance testers use a battery to power the device, and most models inform you of the voltage present with a red light at the tip of the tester as well as a buzzing sound. They come complete with a handy pocket clip so you can carry it close to your heart and always have it ready for safety purposes.

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  • 03 of 07

    Neon Voltage Testers

    neon voltage tester
    © GE

    Neon voltage testers, or neon circuit testers, are as simple as they come. They have a small body with a neon light inside and two short wire leads with a metal probe on each end. Like inductance testers, neon voltage testers tell you only whether a voltage is present or not; they don't tell you how much voltage is in a circuit. 

    To use a neon voltage tester, simply touch one tester probe to a hot terminal on a switch and touch the other to a ground or a neutral terminal. The neon light on the tester will light if there is power. Another way to use it is to insert one probe into one of the straight slots in an outlet and the other probe into the other straight slot of the outlet, much like plugging in a cord. 

    Neon circuit testers are great for DIYers, and they don't use batteries. Use with caution: if you accidentally touch either of the metal probes during a test—and there is voltage in the circuit—you can get a shock. 

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  • 04 of 07

    Plug-In Circuit Analyzers

    Plug-In Circuit Analyzers

    Plug-in circuit analyzers are great, quick electrical testers that fit easily in your pocket and test outlets with ease. These testers are designed to test ordinary electrical outlets, but only grounded outlets that have three holes. Two-slot, or polarized, outlets cannot be tested with the testers because no ground wire is connected to these outlets.

    Plug-in circuit analyzers have a three neon lights that light up in different patterns to indicate specific test results. A chart sticker on the tester helps you interpret the light patterns. Different light combinations signify a correctly wired outlet, a reverse-wired outlet, an open circuit, and the presence or lack of a ground. Circuit analyzers simply plug into the outlet to perform the test, and they don't use batteries. The outlet must have power for the tester to work. 

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  • 05 of 07

    Solenoid Voltage Testers

    Solenoid Voltage Testers

    Solenoid voltage testers, also known by their nickname "Wiggies," are multi-function testers. They are capable of testing both voltage and polarity. Electricians use them frequently because they can test both AC voltage and DC voltage in a range from 100 to 600 volts.

    Solenoid testers have two wires, each with a probe, extending out of the bottom of the tester. One is red and the other is black. Solenoid testers do not use batteries to power them so they are always ready to check voltage accurately. They have a low impedance and will trip ground-fault circuit-interrupter (GFCI) devices or circuit breakers during testing. 

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  • 06 of 07

    Continuity Testers

    Continuity Testers

    A continuity tester is a device that is powered by batteries and has a probe at one end and a cord with either an alligator clip or another probe at the other end. If you touch the two together, you complete a circuit and light is illuminated on the body of the tester, indicating a complete circuit. These testers are great for checking to see if something like a single-pole switch is working properly.

    Tests with a continuity tester must be done with the circuit power off (no voltage). For the same reason, you can test switches and other devices when they aren't even connected to the circuit wiring. Always turn off the power to the circuit or device that you'll be testing!

    Continuity testers are also great for checking wire runs for a complete circuit. You can also use them to find short circuits in wiring. For example, if two wires have melted together inside the outer jacket of nonmetallic (NM) cable. If you touch one tester probe or clip to the white wire and touch the other probe or clip to the black wire, if the tester lights up the wires are identified as being shorted together. 

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  • 07 of 07



    Multimeters are the most versatile of the basic electrical testers and, as their name implies, are capable of many different testing functions. Most multimeters can provide precise readings of resistance, AC and DC voltage, continuity, capacitance, and frequency. 

    Multimeters have a boxy body with a digital or analog readout, a dial for setting the test function (as well as voltage and various readout settings), and two long leads with metal probes at their ends. These testers range widely in quality and accuracy. For DIYers and basic household use, a simple digital multimeter is a great all-around tester to have.