Earth Leakage Circuit Breaker (ELCB) - How It Works

Earth Leakage Circuit Breaker (ELCB) is a type of circuit breaker used in electrical circuits for providing protection against earth leakage fault. In other words, an ELCB is a protection device used to protect people from getting electric shocks in case of an earth leakage fault.

The primary function of an ELCB is to detect and interrupt an electric current that leaks to the ground, which is basically the condition of earth fault.

Read this article to understand the basics, working principle, types, advantages, disadvantages, and applications of Earth Leakage Circuit Breakers.

What is an ELCB?

Earth Leakage Circuit Breaker is a protection device used in electrical systems for detecting the leakage currents and interrupting the circuit.

In an electrical circuit, the electric current flows from source to the load through the phase wire and from load back to the source through the neutral wire. This is how ideally current should flow in a circuit. But in the case of a fault, the electric current can flow from the phase wire to the ground or earth through an unintended path, this current is called as earth leakage current. This unintended path can be through the body of the equipment.

If a person comes in contact with the equipment, he can get an electric shock and injured or died. Therefore, it is important to detect any kind of earth leakage current in the circuit and disconnect the circuit from the source of power. For this purpose, the most commonly used device is the Earth Leakage Circuit Breaker.

Working Principle of ELCB

Under normal operating conditions, the electric current flows from source to load through the phase wire and from load to source through the neutral wire. Ideally, these two currents are equal.

But, in case of a fault, the current flowing through the phase and neutral wires is not equal. This imbalance in the current is detected by the ELCB and interrupted to provide protection.

This is how an ELCB operates to protect an electric circuit from earth leakage fault and a person from an electric shock.

Types of ELCBs

Depending on the operating parameter, ELCBs can be classified into the following two types −

• Voltage ELCB

• Current ELCB

The main function of both types of ELCBs is the same, i.e., provide protection against earth leakage current.

The main difference between voltage ELCB and current ELCB is that voltage ELCBs are older technology and are not being used in modern systems, while current ELCBs are newer and reliable technology and are widely used for protection applications.

Another important fact about current ELCBs is that these are renamed as RCCBs (Residual Current Circuit Breakers).

Voltage ELCB

Voltage ELCBs measure the potential difference between the body of the equipment and the earth terminal. If the potential difference is such that it indicates a leakage current, then the voltage ELCB operates and break the circuit instantly.

Current ELCB

Current ELCB is another type of ELCB which is also known as RCCB or Residual Current Circuit Breaker. This type of ELCB measures the difference between phase and neutral currents. If there is any difference between these two currents, then its operates and break the circuit.

Advantages of ELCBs

The main advantages of ELCBs (Earth Leakage Circuit Breakers) are listed below −

• ELCBs can sense the fault instantly and break the circuit to avoid any kind of equipment failure and electric shock.

• ELCBs reduce the chances of electric faults and fires caused due to insulation failure.

• ELCBs are very efficient in detecting minor earth faults due to their high sensitivity.

• ELCBs are easy to install in the circuit.

• ELCBs are low-cost leakage current protection devices.

Disadvantages of ELCBs

The following are some major disadvantages of ELCBs −

• ELCBs sometimes cause unnecessary tripping of the circuit due to fluctuations in the power supply. Hence, they may result in inconvenience.

• ELCBs are capable in detecting earth leakage faults only. Thus, these cannot provide protection against overloading, short-circuit, or any other kind of severe faults.

• Regular testing and maintenance is required for ELCBs to ensure their reliable operation.

Applications of ELCBs

ELCBs are used in the following electrical circuits to provide protection against leakage currents and earth faults −

• Domestic wiring

• Commercial electrical installations

• Industrial wirings

• Mining or other installations where earthing cannot be done, etc.

Conclusion

Earth Leakage Circuit Breaker (ELCB is a type safety device used in electrical circuit to detect earth leakage faults and prevent the electric shocks. ELCBs are essential components in an electrical circuit to reduce the risks of electric shock or any other kind of accidents.