What is ELCB? Full Form, Function, Diagram, Use

An ELCB is an electrical protective device that protects the electrical from earth leakage fault and protects humans from electrical shock. The full form of ELCB is Earth Leakage Circuit Breaker. When the current flows from the live part of the system to the ground through any conductive part then it is called earth leakage current. This earth leakage may happen due to the insulation failure, accidental contact of the current-carrying part to the non-current carrying part. The earth leakage current fault causes the electrical system unbalanced, unhealthy, unsafe, produce excess heat, etc. So to prevent this fault we need a protective device, that is ELCB.

Function of ELCB

1. ELCB can sense the earth leakage fault. Voltage operated ELCB sense the fault by sensing the voltage and Current operated ELCB( know as RCCB) sense the fault by sensing current.

2. ELCB can measure the magnitude of earth leakage current.

3. ELCB can trip or turn off the main power supply when the earth leakage fault happens, and the magnitude of the current exceeds a limit.

4. ELCB continues monitors if the system is in balanced condition or not.

5. Current operated ELCB can give protection against electrical shock.

Types of ELCB

Based on the working principle, ELCB is classified into two types,
  1. Voltage Operated ELCB
  2. Current Operated ELCB - it is also known as RCCB(Residual Current Circuit Breaker)

ELCB Working Principle

The Voltage Operated ELCB and Current Operated ELCB works in different principle and they have different construction also. Even they need different connections also. Here, working principle of both of them are explained below.

How Voltage Operated ELCB Works?

The working principle of voltage-operated ELCB is very simple. It has a voltage-operated relay and a circuit breaker. The main incoming power supplies are connected through the circuit breaker. And the metallic body of the equipment is to be protected is connected to the earth or ground through the relay coil of the ELCB. Now, when the earth fault occurs the current will flow through the earthing conductor, so a voltage will be applied across the relay coil. Once the relay coil got voltage, it will be energized and it will send a signal to the circuit breaker to break the circuit. Voltage operated ELCB must need a connection to the ground. Voltage operated ELCB will work only when the fault current flow through its coil only, it cannot detect the fault happen any other places in the circuit.

Voltage Operated ELCB Diagram

Here you can see the diagram of Voltage Operated Earth Leakage Circuit Breaker.

Voltage operated ELCB Diagram, Earth Leakage Circuit Breaker Diagram

How Current Operated ELCB Works?

The current operated ELCB or RCCB works in a different way. It also has a circuit breaker that will break or make the contact to turn off or turn on the main power supply. Generally, it has a core balance current transformer. All the conductors from the power source to load are goes through this current transformer. 

In normal conditions, when there is no earth leakage fault a balance current flows through the circuit. But when an earth leakage fault occurs, an unbalanced current flows through the circuit. The current transformer will sense the unbalancing and send a signal to the relay. And the relay will send a signal to the circuit breaker, so the circuit breaker will break the circuit to turn off the incoming power supply. Current operated ELCB does not need connection to the earth. It can sense or detect the fault happen anywhere in the circuit.

Current Operated ELCB Diagram

Here, you can see the diagram of current operated ELCB or RCCB.

Current Operated ELCB Diagram, Earth Leakage Circuit Breaker Diagram

Application and Uses of ELCB

1. Voltage Operated ELCB is mostly used in older days to protect motors,  electrical power distribution panels, etc.

2. Current Operated ELCB or RCCBs are modern and they are used everywhere from domestic to industrial protection. You cam see its application from your home to office everywhere.

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What is ELCB? Full Form, Function, Diagram, Use What is ELCB? Full Form, Function, Diagram, Use Reviewed by Author on December 12, 2021 Rating: 5
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