How to Identify Neutral Wire with a Multimeter (4-Step Guide)

If you’re an apprentice or do it yourself and are trying electrical work, you should know how to identify different types of electric wires – the live (a.k.a. hot), neutral, and ground wires. You can easily trace the cause of inconsistencies in your systems by recognizing and fixing the open neutral points.

Some inexperienced electricians may mix up the wiring, so you cannot always rely on color codes to tell a neutral wire from the other two wires.

So, how can you recognize a neutral wire if the wiring harness is jumbled up? Well, you need to use a multimeter or a tester. I have been an electrician for over a decade, and today, I will teach you how to use a multimeter to single out a neutral wire from any connection.

Identifying the neutral wire can be done with a multimeter. After setting the multimeter at its highest voltage, you can easily identify the neutral wire using its black and red probes. 

Different Types of Circuit Wires

There are three types of wires that you might encounter at your home. Therefore, having proper knowledge can benefit you if you plan to do a repair or an inspection.

Live Wire: This brown wire conducts the electricity from the main power supply to the other devices.

Earth Wire: Comes in yellow or green colors. This wire conducts electricity to the ground, preventing the current flow through a broken circuit breaker called the CPC.

Neutral Wire: This blue wire carries electricity from a device to the power source. In other words, a neutral wire completes the system or a circuit.

4-Step Guide to Recognizing a Neutral Wire with a Multimeter

It is necessary to distinguish neutral, live, and ground wires in any electrical fixture before a repair. Without knowing which wire is for what, you cannot wire new electrical components like bulbs and sockets in a fixture. So, the following steps will help you.

Step 1: Safety First

Safety is integral to any process that may cause severe or mild damage. The dangers of electricity – electrocution or shock, are well-known issues with wiring. So, always turn off the main power supply before you begin wiring.

Step 2: Wall Outlet/Socket and the Multimeter

If your wall outlet has a plastic cover, use a screwdriver to remove the screws and the cover, and then bring out the three wires from the socket.

Now, set your multimeter to the highest voltage reading. Since you will be dealing with alternating current, set the multimeter range to AC.

Step 3: Using the Black Probe

If the multimeter probe leads are not inserted in their respective ports, insert the correct end of the black probe into the socket labeled com. Plug the red probe into the port with the v label.

Connect the black probe to a grounding surface such as a fridge, water pipe, or faucet. At this point, the multimeter should not display any value yet.

Step 4: Testing the Neutral Wire with the Red Probe

Before testing the neutral wire, calibrate the multimeter by pinging the probes. You should hear a sharp beeping sound. Your multimeter is ready.

You can use a wire stripper to strip off the insulation of the three wires to about ½ inch if the terminals are not well-exposed.

Now touch the red probe lead to the stripped terminals of the three wires – while the black probe remains grounded. Now, touch the probe on the remaining wires. If you get a voltage reading for any cable, that wire is hot or live. Of the two wires, the one that does not give a voltage reading is the neutral wire.

Precautions to Take When Testing a Neutral Wire

  1. Have your safety gear on, and use a probe. You should have your safety goggles and insulated gloves. The goggles protect your eyes from flashes and sparks, while the insulated gloves curb electrocution if you touch a live wire. You may also want to remove metallic objects from your pocket before you begin the process.
  2. Do not touch live surfaces That contain electrical charges while using a multimeter. Hold the insulated or rubber parts of the multimeter.
  3. Turn off the main power supply If you are new to wiring. Doing so will be much safer; working with a live circuit is dangerous for beginners.
  4. Avoid working with wet hands or standing on wet surfaces When testing for a neutral wire.

Frequently Asked Questions – Faqs

How Can I Tell a Neutral Wire from The Ground and Live Wires?

wiring colour changes

The easiest way to pinpoint a neutral wire is to know the color code. Neutral wires are blue, live wires are brown, and ground wires are green. Your country’s color codes may differ; make sure you know them.

However, that is not the best method to use to identify wires. Some electricians may decide to mix up the colors, which is unacceptable and dangerous. So, always use a multimeter test to check the wires to be safe.

You may also use a tester; hot wires have 220 or 230 volts whilst neutral wires have zero volts.

What is an Open Neutral Connection

Open neutrality is a situation where two points lose the neutral wire link; hence, there is no neutral connection between the two points. Open, neutral points can disconnect the system or cause inconsistencies.


Website Resources:

Video References:

The Engineering Mindset


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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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