Why Does My Neutral Wire Have 120 Volts? Solved

Why Does My Neutral Wire Have 120 Volts? | howtoimprovehome.com

It can be hard and confusing to figure out how the electricity works in our homes. 

Finding out that the neutral wire in their electrical system has a voltage of 120 volts is something that many people find confusing. It is a big problem because a neutral line should normally have close to zero volts. 

In this piece, we’ll look into why this strange thing is happening and explain the role of the neutral wire, how it works in your electrical system, and why a 120-volt reading could mean a dangerous situation that must be fixed immediately. 

Why Does My Neutral Wire Have 120 Volts?

This abnormal reading is the result of issues including shared neutral or bootleg ground, neutral-to-earth voltage problems, poor transformer connections, load imbalances, or open neutral wires. Moreover, a faulty appliance may also cause the voltage to be supplied to the neutral wire. 

Shared Neutral or Bootleg Ground 

A shared neutral or a bootleg ground could explain why a neutral wire has 120 volts. In some situations, a person who doesn’t know what they’re doing or isn’t qualified could incorrectly connect the neutral wire to the ground wire, making a shared neutral or “bootleg ground.” 

It can cause the neutral wire to carry electricity, giving you 120 volts. To fix this problem, you need to separate the ground and neutral wires to ensure they are not connected.

Why Does My Neutral Wire Have 120 Volts? | howtoimprovehome.com

Neutral-to-Earth Voltage

When everything is normal, there may be a small amount of voltage between the neutral line and the earth’s ground. It is called neutral-to-earth voltage. It is mostly because of how the electricity distribution system is made and the resistance between the neutral and the ground. 

Most of the time, a small voltage (a few volts) is fine, but a bigger neutral-to-earth voltage could mean there are problems with grounding or other electrical problems. In this case, you should talk to an electrician to check the grounding system and find any possible problems.

Faulty Transformer Connection

Rarely, a weak link in the transformer can result in a high voltage on the neutral wire. It can happen if the transformer has loose links or bad wiring. Only a qualified electrician or utility company should take care of transformer issues. Calling the utility company to report the problem is a good idea since they have the knowledge and power to fix problems with transformers.

Load Imbalance

A load imbalance happens when electrical devices draw different amounts of power at different stages. It can cause too much current to run through the neutral wire, which builds up voltage. 

To solve this problem, the load should be spread out evenly across the different stages. It can be done by moving electrical devices or using load-balancing methods, like using three-phase power if available.

Why Does My Neutral Wire Have 120 Volts? | howtoimprovehome.com

Open Neutral

The neutral wire is broken or detached in the electrical circuit, which causes an open neutral. When this happens, the neutral wire loses its ability to carry the return current well, which causes the voltage to change. 

To find and fix an open neutral, you need to look at the wiring and junction boxes for any neutral wires that are loose or broken. If the bad wiring is fixed or replaced, the neutral wire should work as it should.

Why Does My Neutral Wire Have 120 Volts? | howtoimprovehome.com

What is Acceptable Neutral Voltage?

In a properly balanced system, this voltage should be 0 in the best case. However, in real life, this voltage is not always zero because of system imbalances brought about by uneven load distribution or harmonic currents. Moreover, connection problems could also lead to voltage in neutral.

Neutral voltage is very important in knowing how electricity is distributed, especially in three-phase circuits. Most of the time, neutral voltage is the difference between the voltage at the neutral point and the voltage at the earth’s ground. 

Before you can understand the neutral voltage, you need to know what the neutral line does in a power system. In a three-phase power system, the neutral wire lets the electricity return to where it came from. 

It lets the system ensure that each phase gets the same power. Referring to the neutral point, the sum of the voltages in the three stages of a balanced system equals zero. So, the best voltage from neutral to the ground is zero. But a neutral-to-ground voltage that is not zero can happen when there are imbalances in the circuit.

An imbalance happens when the load isn’t spread out evenly between the three phases. It causes current to flow through the neutral wire, which causes the voltage across it to drop because of its resistance. It means the voltage from the neutral to the ground is not zero. 

In the same way, non-linear loads like computers and other electrical devices can cause harmonic currents, which change the shape of the voltage waveform and make the neutral-to-ground voltage go up.

The term “acceptable neutral voltage” refers to the amount of neutral-to-ground voltage the power system can handle without causing problems or raising safety concerns. 

Why Does My Neutral Wire Have 120 Volts? | howtoimprovehome.com

How Do You Reduce Neutral Voltage?

One of the best ways to lower neutral voltage is to ensure all the system loads are balanced. When you balance the loads, you ensure that each part of the system carries the same amount of current. It can be done by spreading single-phase loads carefully across all three phases. 

Load balancing not only helps lower the neutral voltage but also improves the system’s general performance, makes it less likely that it will overload, and makes it more efficient.

Getting the grounding right is another important part of lowering the neutral voltage. According to the National Electrical Code (NEC), the neutral line should have good ground. Grounding the neutral line helps keep the voltage levels in the system stable and gives the current a clear path to follow in case of a problem. 

Neutral voltage is also partially managed by ensuring the electrical system is regularly checked and fixed. Any electrical problems, loose connections, or broken equipment should be found right away and fixed. High-quality lines and components with the right ratings can also stop the voltage from dropping or going up when it shouldn’t.

Harmonics in the circuit can also make the neutral voltage higher. It is because loads that aren’t linear, like computers, LED lights, and varying frequency drives, create harmonic currents that can make the neutral voltage higher. This problem can be made less of a problem by installing harmonic filters or using devices with power factor adjustment.

Lastly, you might use a neutral converter or an advanced neutral voltage reduction device. When these devices are put into the power system, they can help lower the neutral voltage by creating a voltage that cancels out the extra neutral voltage.


If a neutral wire has 120 volts, it means there is an electrical problem that needs to be fixed right away because it could be dangerous. Several things could cause this strange reading, such as a shared neutral or bootleg ground, neutral-to-earth voltage problems, bad transformer connections, load imbalances, or an open neutral line. 

Additionally, a malfunctioning device might be the problem. A skilled electrician has the knowledge and skills to correctly figure out what’s wrong and fix it. A well-balanced electrical system is linked to the idea of an “acceptable” neutral voltage. 

In an ideal world, the neutral voltage would be 0 volts, but system flaws and harmonic currents can cause this to not always be the case. Keeping this neutral voltage as low as possible is important for maintaining an electrical system that works well and is safe.

Load balancing, proper grounding, regular repair, and using high-quality lines and parts are all ways to lower neutral voltage. To lessen the effects of non-linear loads, you can also use harmonic filters or devices that change the power factor. 

Neutral inverters or other advanced neutral voltage reduction devices could be used in the worst cases. So, a reading of 120 volts on a neutral wire isn’t just a strange electrical quirk; it’s a serious problem that needs to be fixed quickly to avoid harm and electrical inefficiency.

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