How to Use a Voltage Tester

Electrical components are all around us and whether you are a professional or a DIYer, you must know they are bound to get run into problems every so often so do you check if they are working properly? Well, that is where a voltage tester comes into play.

A voltage tester is used to detect an electrical current in a variety of electrical components, including light switches, electrical outlets, and light fixtures. There are assorted voltage testers out there, and each one is used differently. The most common ones include a multimeter, an electrical outlet tester, and a non-contact voltage tester.

In this guide below, we have detailed everything that you need to know about using the three aforementioned voltage testers.

So, without further ado, let’s get started!

Method 1: Through a Multimeter

How to Use Voltage Tester

A multimeter is basically a two-lead voltage tester, that shows you the exact voltage it measures.

Step 1: Power on the Multimeter

Alright, so the first and the foremost step is simple; you just have to plug in the voltmeter and power it on.

Step 2: Placement of the Probes

Since a multimeter is a two-lead probe, it has two probes or wires.

The black wire is used for measuring the ground or neutral wires whereas the red wire connects to the hot wire, i.e., the wire carrying the current.

For an electrical outlet, connect the black wire to the port, with a minus sign or with the “COM” label (it is also the larger of the two ports on an electrical outlet). In the contrast, connect the red wire to the port with a capital “V” next to it.

For a battery, the black probe connects with the negative terminal and the red probe with the positive one whereas, for electrical wiring, the black probe goes with the exposed green or white wire and the red probe with the exposed black wire.

Note that there are accessories, available in the market, for your probes as well, such as banana plugs and alligator clamps.

Step 3: Choose the Voltage Mode

A great many multimeters come with a dial-in front, that allows you to select the mode and the range of measurement you are expecting.

Rotate the dial so that it is set at either direct current (DC) or alternating current (AC) mode. DC usually has a V with a straight line next to it whereas AC usually has a V with a wavy line next to it.

Once in either the DC or the AC range, turn the knob until you are close to the voltage reading that you are expecting. For instance, for a 12 V battery, you would want the dial to be set at 20 volts, rather than 2000 volts.

Step 4: Read the Meter

With everything in place, all you have to do now is read the reading on the multimeter.

Method 2: Through an Electrical Outlet Tester

Electrical Outlet Tester

An electrical outlet tester is the most basic voltage tester out there. It consists of three lights and a chart, that shows if there is any problem with the outlet. You have to plug it directly into an electrical outlet.

Once plugged in, the electrical outlet tester will show the results that it obtains and you just need to have a knowledge of how to read those results.

Essentially, there is a key on the side of an electrical outlet tester, indicating what each of the three lights means. Normally, the red light represents the voltage to the ground/green wire, the first yellow light represents the voltage to the neutral/white wire, and the second yellow light represents the voltage to the hot/black wire.

Here are some of the common readings and that you can expect using an electrical outlet tester:

  • Correct: When the red light is dark and both yellow lights are lit up, the outlet is working properly. If the yellow lights are dim, then that is the indication of a wire being in a poor state.
  • Open Neutral: When the first yellow light is dark, but the second yellow light and the red light are lit then that is the indication of the white wire, not receiving any electricity; it would either be disconnected or need to be replaced.
  • Open Hot: When all the lights are dark, that is the indication of no electricity coming from the black wire. This could be because the wire is disconnected or the electricity is shut off.
  • Open Ground: When the first yellow light is lit, but the second yellow light and the red light are off, then that is the indication of the green wire not receiving any electricity; it would either be disconnected or need to be replaced.

Method 3: Through a Non-Contact Voltage Tester

Non-Contact Voltage Tester

A non-contact voltage tester allows you to detect the presence of an electrical current, without any physical contact with electrical components or wires. So, they are the safest of all voltage testers.

Step 1: Turn on the Non-Contact Voltage Tester

First off, just as in the case of a multimeter, you need to turn on your non-contact voltage tester by pressing the power button. In some cases, you may need to press and hold the power button to turn on the device.

In any case, however, the device will give you some sort of indication, such as a light or a chirp, to show that it is being turned on.

Step 2: Test the Device

In order to make sure that your voltage tester is working properly, you need to run a test on it.

Accordingly, place the tip of the device in the shorter slot of an electrical outlet or touch the bulb of a lit lamp.

Step 3: Test the Desired Electrical Component

Once you have ensured that your non-contact voltage tester is working just fine, you can use it to test the voltage to any electrical component of your choosing. For your convenience, below, we have outlined some of the most common components that you can test using a non-contact voltage tester:

Electrical Outlet

Electrical Outlet

In order to test an electrical outlet with a non-contact voltage tester, touch the tip of the device to the smaller slot on the receptacle of the electrical outlet. You can also check the larger slot on the receptacle for ensuring that the outlet is wired the right way.

Breaker Switch

For the breaker switch, you simply need to touch the tip of the non-contact voltage tester to the switch in the panel of a breaker box.

Light Switch

For testing the light switch, first, make sure that it is turned on. Now, remove the faceplate from the wall and then, touch the tip of the non-contact voltage detector to the screw terminals, located on side of the light switch.

Note that for a three-way switch, you should test all the screw terminals on both switches before proceeding.

If the light switch doesn’t show any sign of an electrical current, you can assume it is safe to be removed.

Light Fixture

Firstly, turn on the light. Unscrew the light-bulb and position the tip of the non-contact voltage tester inside the light socket.

Note that if the light has a three-way switch, you need to run the test with the switch in both up and down positions.

When you have made sure there is no electrical current, running through the light fixture, you can safely remove it from the ceiling.

Frequently Asked Questions

Will I Get a Shock if I Touch Neutral?

No, you won’t since a neutral wire is connected to the earth, directly or indirectly. If the neutral wire is not grounded, then you would get a shock.

How Do I Use a Voltage Tester to Check Incoming Voltage in a Distribution Box?

It may seem a bit intimidating but it is the same as any other voltage test. To get into the power input wire, turn the breaker off the box, and open the wire to get to the metal inside. Now, use the voltage test on wiring to get the results.

What is the Easiest and Safest Way for a Homeowner to Check if a Gadget Has Been Fully Switched off From the Mains?

The easiest and safest way is to use a voltage tester.


And that brings to an end our comprehensive guide on how to use a voltage tester.

To reiterate, a voltage tester is a device used to detect electrical current in an electrical component. The use of a voltage tester depends on its type. However, the most fundamental steps are plugging in the device in the right slot on the concerned electrical component, or bringing the device near it, and then waiting for reading or some sort of indication of an electrical current.

Liam Weissman

Hello and welcome to PowerToolGenius! My name is Liam and for the last 9 years, I have worked extensively with various power tools and accessories. I have tested hundreds of different brands and models and understand the industry extensively and have been working with tools my entire life!

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