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How to use a Multimeter to test the Voltage of Live Wires

Electrical wires carry electricity. A live wire carries high voltage and can be dangerous if you contact it directly. Still, an earth (or ground) connection limits the damage caused by these potentially fatal incidents by limiting exposure time for most people to just minutes or seconds before they die from massive electrical shock where there would otherwise have been no injuries at all because of their bodies are not designed for such intense energy waves which we call “electrical current.” In this Article we will learn How to use a Multimeter to test the Voltage of Live Wires.

How to use a Multimeter to test the Voltage of Live Wires

Voltage is an important concept in electricity. We’ve all heard the phrase, “checking voltage on a live wire,” or maybe even done it ourselves at some point – but what does this mean? This process identifies any differences between cables connected to metal surfaces (i.e., wires) by comparing them against one another until they’re equal; outwardly flowing currents are cancelled out & no longer exist.

What is a Multimeter?

The Multimeter is an instrument that can measure voltage, amperes and ohms. This versatile tool will be needed whenever one needs to check the electrical current in wires, or else it would not function properly with any other device. It’s known as a VOM (volt-ohm meter) because its three ranges make up for all those necessary measurements.

This article will show you how to measure voltage with a multimeter. We’ll start by discussing the technique and then move on in detail for each step of this process so that there are no doubts or confusion about what needs doing at any given time.


When it comes to an understanding how a multimeter works, one must know the basics. You’re probably wondering what they look like or if you ever had questions about where certain parts go? Don’t worry about that now! We’ll explain everything else for now, and then later, we can talk more in-depth if needed.

Multimeters are used for testing the continuity of electricity. They have three parts- a screen, selection knob & two or more ports where you can plug in your probes that will allow them to make contact with ground and circuit, respectively, when needed most.

Steps to Use a Multimeter to Test Voltage of Live Wires

Step 1: Safety is the most important thing

Safety is one of the most important things to keep in mind while dealing with an AC as high as 120 volts or 220. You should always ensure you’re safe and not touching anything near any exposed terminals on your device, especially if other people around might be shocked by a mistake.
● Touching live wires is never a good idea. Even if you only plan on fixing or moving the cable, wear an insulating glove to prevent accidental contact with power lines.
● When measuring values in an AC circuit, change the Multimeter‘s mode from DC to AC each time you want to access it.
● Always start your testing with the highest current range.
● It is important to de-energize and discharge the circuit before connecting or disconnecting a multimeter.
● When measuring resistance with a multimeter, you should never apply power.

Step 2: Set the Parameters

What can be more important than knowing how much voltage runs through your circuit? The milli-meters are designed with three different modes that will allow you to measure both high and low energy levels, meaning they’re perfect for any project.
This device has an easy interface, so all it takes from there to set them up properly should select “Voltage” when entering into the settings menu.”
● Use the part labelled “V” and a wavy line to measure AC.
● Use the part labelled “V” and a straight line to measure DC.
● A Multimeter is an essential tool for troubleshooting any electronics project, and it can measure voltage within the range of 200 mV-600 volts AC or DC.

Step 3: Plugin Probes:

If you are using a three-port multimeter, it comes with:

● The common port to measure the negative or ground is known as COM.
● With this device, you can measure up to 200 ma of current and voltage with precision.
● The 10A current range is perfect for testing meters and other high-current devices.
It’s easy! Just plug the probes into the right ports, and you’ll get accurate measurements.

Step 4: Actual Testing:

To ensure the Multimeter is functioning properly, test it on a real live wire.

1st Approach: The red probe on the live cable and the black one in neutral. The readings appeared.

2nd Approach: The black probe on earth wire and red Live Wire. You will get the reading.

Are you Getting a Negative Reading?

You may have reversed the positions of the Black and Red probes. Always remember a Multimeter measures voltage on life to common (COM) ports, so make sure you’re using them correctly.

Step 5: Taking the Reading:

There are two cases in terms of readings when you check a live wire through a multimeter. 

Case 1: When the fixture is live, there’s a voltage between 110 and 120 volts flowing through them.

Case 2: When you have a zero on your display screen, there’s no voltage in the wire. In other words: No current flows through them.


Wondering why you need to check the voltage of a live wire? We’re here with some answers for you. Electric hazards are dangerous and can result in serious injury or even death, so knowing your current level is essential when handling them! Apart from this, it also helps diagnose any malfunctioning issue, which will make fixing things easier on us all – thanks very much 🙂

A multimeter is an essential tool that can be used for many other purposes, such as measuring amperage (How to Tune an Amp with a Multimeter) and resistance.
In addition, it has been shown by professionals in their field who understand just what this small box does best – capacitance testing.

Syed Muhammad Jawad

System Analyst / Founder / CEO

Explore comprehensive, expert reviews of electronic multimeters by Syed Muhammad Jawad, the respected author and electronics enthusiast. Delve into his insightful analysis, detailed comparisons, and trusted recommendations to make informed decisions on your next multimeter purchase.