How to Use a Multimeter to Test Voltage of Live Wires – Measure Twice, Stay Safe

How to test voltage with multimeter

Got a complex-looking multimeter with knobs but cannot figure out how to bring it to use? And you are considering checking some parameters of a live wire through this device, which might add to the stress. Why?

A live or hot wire is through which very high current flows. It is used to charge several appliances. Careless handling of these cables can lead to serious injuries, even death. Therefore, people take several precautions to allow safe procedures.

Faulty or poorly insulated hot wires might prove dangerous, can cause a fire hazard, and result in malfunctioning electrical devices. In this regard, multimeters facilitate in many ways by providing the measurement of voltage.

It allows one to avoid any accidents and repair defective wires. For your convenience, I have mentioned the procedure for using this device step by step in addition to the guidelines that one must follow. You have got this.

Use a Multimeter to Test Voltage of Live Wires – Guide

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Basic Knowledge About Components

Before you start using something, it is necessary to have sufficient information about its parts and functions. Only then can you make effective use of it. So, let us learn about a multimeter. It has three components: a digital screen, two or more ports, and a knob.

Usually, the screens include a panel that shows measurements in four digits. The knob allows a person to select the property that one wants to know (for instance, voltage). The ports allow plugging in the probes, which have been connected to either earth or any circuit for testing the parameter.

Procedure for Using a Multimeter for Live Wires

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Safety Precautions

While doing these kinds of tasks, safety comes first. Therefore, before you jump into making connections, you need to make sure that you are working in a safe environment. During dealing with higher alternative currents in the range of 120 to 220 Volts, remember to not touch a hot wire without wearing any protection.

One can subconsciously touch it even when being extremely careful. So, it is better to put on a pair of gloves that provide adequate insulation.

For knowing the AC value in the circuit, always shift the multimeter’s mode from direct current to AC. Moreover, make sure you discharge the circuit entirely before you connect the measuring instrument as well as after noting the readings. When measuring the resistance, do not connect the multimeter with the circuit.

Setting Parameters

As you know that a multimeter or multitester can cater to multiple parameters, so for measuring voltage, use the selection knob to convert this device into this mode (Voltage). If you want to measure AC, look for the component that shows a V symbol with a wavy line.

Similarly, if you are interested to note DC, use the component that shows V along with a straight line. A standard multimeter can efficiently measure and detect this parameter between 200 mV (milliVolts) and 600 V.

Connecting the Probes

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The next step involves joining the probes with the appropriate ports. There is a possibility that a three-port device is available to you. It includes a common port for measuring the ground (negative) of the parallel circuit.

The part labeled as mAVΩ measures all three: the current, voltage, and resistance. Finally, the purpose of a 10A port is to measure high or strong currents. Your job is to form the connection between the two probes and the correct port. It depends on your personal preference, which in this case is voltage.

Checking the Proper Functioning

It is time to test whether the multimeter is working accurately by joining it with a live wire. There are two main approaches that are involved in this process. The first one involves plugging the red probe into the hot cable and the black into the neutral or ground cable. Note down the reading that will appear on the screen.

The second method involves the connection between the red probe and live wire and the black one with the other. A measurement will appear on display. If you get a negative reading, the chances are that you have reversed the arrangement of both probes. Remember that this instrument is able to measure the parameter V of high-current wire to the COM port and not the other ports.

Noting Down the Reading

After you have put everything in its position, the multimeter will display the voltage of the live wire. There are two possibilities regarding these measurements. If you observe the value of 110 and higher, the cable is live. On the other hand, your multimeter might show no voltage and read it as zero. It means that the cable is neutral, and no current passes through it.


What can be tested with a digital multimeter?

Through a digital multimeter, one can easily measure the polarity and the voltage of the cables in the circuit.

What should you do before you connect a multimeter to a circuit?

Before connecting a measuring device to the wire, make sure to check whether the switch is in the correct position. In addition, check the connections in the circuit with extreme care.

How do you read voltage with a multimeter?

For this purpose, turn the knob to symbol v. Now insert both the red and black leads into the VΩ port and the common jack, respectively. Connect both leads with a circuit and note down the measurement that the device displays on its screen.

What is a voltage parallel circuit?

A circuit for measuring potential difference or voltage involves the adjustment of wires so that the same reading of potential difference is observed across multiple components. One can make a parallel arrangement by making connections among the terminals of electric devices.

Is it safe to measure voltage with a multimeter on live wires?

It can be safe to measure voltage with a multimeter on live wires, as long as you take proper precautions and follow safety guidelines. This includes wearing appropriate protective gear, ensuring the multimeter is properly set up and connected, and avoiding contact with the live wire.

What is the difference between AC and DC voltage measurements?

AC (alternating current) voltage is used in most household electrical systems, while DC (direct current) voltage is typically used in electronics and batteries. AC voltage changes direction over time, while DC voltage flows in one direction. To measure AC voltage, you need to use the AC setting on your multimeter, while for DC voltage you need to use the DC setting.

How do you test for continuity with a multimeter?

To test for continuity, you need to use the continuity or ohms setting on your multimeter. This will allow you to determine if there is a complete electrical path between two points in a circuit. To test for continuity, connect the probes to the two points you want to test, and listen for a beep or see a reading on the multimeter screen.

Can a multimeter measure current and resistance as well as voltage?

Yes, most multimeters are designed to measure current, resistance, and voltage. To measure current, you need to use the current setting and connect the probes in series with the circuit. To measure resistance, you need to use the ohms setting and connect the probes to the two points you want to test.

What is the maximum voltage a multimeter can measure?

The maximum voltage a multimeter can measure depends on the specific model and design. However, most multimeters are capable of measuring voltages up to 600 volts AC or DC. It is important to check the specifications of your multimeter to ensure it is suitable for the voltage range you need to measure.


I hope that you have gained sufficient knowledge about the procedure of using a multimeter tool for live wires. It is an amazing instrument due to its versatility. While working and handling electric wires, be cautious and do not allow children near that area. It is better that you get success in your task without hurting yourself. Also, if you still find any difficulty in following the instructions, I recommend seeking help from someone who is an expert in this field.

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