Difference between Neutral and Floating Neutral

In the field of electrical and power distribution engineering, there are two important concepts namely neutral and floating neutral. The neutral, also called neutral wire, is a return path for electric current in electrical circuits that balances the phase loads and serves as a reference point. In practical applications, the neutral is typically grounded at the main panel or distribution end.

On the other hand, the floating neutral is also a neutral wire but it is isolated from the ground terminal. The concept of floating neutral is not much common in practical applications, but it may be used in some specialized applications where we do not need to ground the neutral wire for any reason.

It is also important to note that the neutral configuration provides improved safety and stability in an electrical system, as it is connected to ground. Whereas, the floating neutral configuration being an ungrounded system can pose some issues related to voltage fluctuation, faults, and safety.

Therefore, the neutral and floating neutral are two distinct concepts in electrical engineering. This article is meant for explaining the key differences between neutral and floating neutral in terms of their meaning, characteristics, configuration, applications, and more. But before, let get a brief overview of these two concepts individually.

What is Neutral in Electrical?

In electrical systems, the neutral or neutral wire acts as an important component, as it completes the circuit and ensures the safe operation. In any electric circuit, the neutral wire is a conductor that provides a return path for electric current and completes the circuit so that the electric current can flow back to the supply source like battery or generator.

In practical electric circuits, the neutral is typically connected to the ground terminal at the main supply panel or distribution board. This ground connection maintains the potential of neutral to ground or 0 V.

Thus, in an electric circuit or systems, the neutral serves the following two purposes −

• In a multiphase electrical system, the neutral wire balances the load across the different phases of the system by carrying the unbalanced load current. This helps in preventing any voltage fluctuations.

• Since the neutral is connected to ground terminal, thus it improves the electrical safety by providing a path of low electrical impedance for the flow of leakage or fault currents. This minimizes the risk of electric shocks and fire hazards due to faults.

Also, the neutral wire provides a reference point in the electrical systems that can be used to perform voltage measurements. Hence, the neutral wire is a crucial component in an electrical system. It is essential for an electrical engineer to understand its function and importance to design, install, and maintain an electrical system effectively and safely.

Let us now understand another concept to be covered in this article which is floating neutral.

What is Floating Neutral in Electrical?

In electrical systems, a floating neutral is a neutral wire which is not connected to the ground terminal. Hence, an electrical system with a floating neutral is also known as an ungrounded system. Therefore, when the neutral conductor is isolated from ground terminal, then it is referred to as floating neutral.

A floating neutral offers several unique characteristics. Some of the key characteristics of the floating neutral are listed below −

• In a floating neutral configuration, the neutral conductor is not connected to the earth or ground terminal.

• Since the potential of the neutral conductor is not referenced to the ground potential in a floating neutral configuration. Thus, its potential can fluctuate significantly depending on the load conditions of the system.

• The floating neutral cannot redirect the fault current to the ground, thus it cannot provide protection against fault conditions and may pose the risk of electrical shock and equipment damage.

• Floating neutral does not provide a stable reference point, hence it offers difficulties in voltage measurements and troubleshooting jobs.

Therefore, floating neutral is a less commonly used type of neutral configuration in electrical systems. But it is mainly used in some specialized applications where grounding of the neutral wire is not possible or undesirable. Some common examples where the floating neutral system is used include portable generators and isolated power systems.

Difference between Neutral and Floating Neutral

The key differences between neutral and floating neutral are highlighted in the following table −

Parameter	Neutral	Floating Neutral
Definition	Neutral or neutral wire in an electric circuit is a conductor that provides a return path for the flow of electric current from load to the source.	A floating neutral is a type of neutral wire which is not connected to the ground terminal in the system. In other words, a neutral wire not connected ground and left free to float is called floating neutral.
Purpose	In electrical circuits, the main purpose of neutral is to complete the circuit and provide safe and balanced operation.	Floating neutral is used for specialized purposes to fulfil some specific electrical or safety needs in the circuit.
Connection to ground	Neutral wire is generally connected to the ground terminal at the main supply panel or distribution board.	Floating neutral is not connected to the ground terminal or it is intentionally separated from the ground.
Reference point	Neutral provides a stable reference point for the measurement of voltage, its voltage is considered equal to ground voltage.	Floating neutral cannot provide a stable reference point for measurement of voltage in the system. This is because it is not connected to the ground.
Safety	Neutral being properly grounded improves the electrical safety and minimizes the risk of electric shock and fire accidents.	Floating neutral is isolated from ground, hence it cannot provide any kind of electrical safety.
Protection against ground faults	Neutral is properly grounded, therefore it can detect and manage the ground fault conditions effectively.	Floating neutral is not effective in detecting and managing the ground faults.
Voltage fluctuations	Neutral provides a low-impedance path for the flow of fault currents. Therefore, it contributes in voltage stabilization.	Floating neutral does not have grounding, thus it results in voltage fluctuations depending on the load conditions.
Electromagnetic interference reduction	Neutral has proper grounding which helps in reducing the effect of electromagnetic interference.	Floating neutral cannot provide any corrective action against electromagnetic interference.
Application	Neutral is mainly provided to complete the circuit, and ensure safety and stability. It is commonly used in all residential, commercial, and industrial electrical systems.	Floating neutral is used in applications where the grounded neutral is not desirable or practical like in portable generators.

Conclusion

For an electrical engineer, it is crucial to understand these concepts for designing, installing, and maintaining safe, efficient, and reliable electrical circuits and systems. In conclusion, the neutral and floating neutral are two distinct concepts in electrical systems with a most significant difference that is a neutral is a conductor connected to the ground terminal at the main supply panel, whereas the floating neutral is a type of neutral conductor which is intentionally isolated from the ground.

FAQs Related to Neutral Vs Floating Neutral

Some of the most frequently asked questions related the concept of neutral and floating neutral are explained below.

1. Does the neutral wire carry any current?

Neutral wire is a conductor in an AC circuit. In a single-phase ac circuit, the neutral wire acts as a return path for the current from load back to the source. Hence, it always carries an electric current. But, in the case of three-phase ac circuit, the flow of current through the neutral wire depends on the load condition. If the three-phase load is balanced, then no current will flow in the neutral, but when the load is unbalanced, the neutral wire carries a current depending on the load condition.

2. What is the use of floating neutral?

Floating neutral system is not very commonly used in electrical engineering. But it is used in some specialized applications where it is not practical to use a grounded neutral. Some of the common uses of floating neutral are listed here −

• In portable generators to provide safe and stable operation.

• In isolated power systems used in remote locations like marines.

• In electrical systems that require ungrounded neutral, etc.

3. What is an example of a floating neutral?

A floating neutral can be seen when a neutral wire is broken or separated from the ground terminal of an electrical system. It is the most common example of floating neutral that we see in our practice.

4. How do you identify a floating neutral?

To identify that the neutral is floating or not, just measure the potential difference between the neutral and ground terminals. If this reading is not equal to 0 V, that means the neutral and ground are not at the same potential. This indicates the condition of floating neutral.

5. What happens if neutral is floating?

In electrical systems, a floating neutral occurs when the neutral wire is isolated from the ground terminal. If a floating neutral occurs in a system, this can create some technical and safety issues that can lead to electric shock or fire or unstable system operation.