What is ELCB? Principle, Advantages, Disadvantages, Applications

What is ELCB?

An Earth-spillage electrical switch (ELCB) is a wellbeing gadget utilized in electrical establishments with high earth impedance to forestall shock. It identifies little wanderer voltages on the metal nooks of electrical hardware and interferes with the circuit assuming the voltage level surpasses risk edge


Two varieties of ELCBs exist.

  1. Circuit Breaker for Voltage Earth Leakage (Voltage ELCB).
  2. Circuit breaker for current earth leakage (Current ELCB).

1 Voltage Earth Leakage Circuit Breaker

Voltage A voltage-operated circuit breaker is an ELCB. When the current crosses the ELCB, the device will work.

The relay coil inside the voltage ELCB is attached to the metal body on one end and the ground on the other.

Purpose of operation

Electric shock risk will arise if the voltage of the equipment body increases due to either equipment insulation failure or contact between phase and metal elements, which may result in a differential between earth and body load voltage.

A current of electricity is produced by this voltage difference and travels from the load’s metal framework via the relay loop and to ground.

In order to prevent dangerous electric shock, the relay contact could be moved by the current running through the relay loop when the voltage on an appliance or piece of equipment’s metallic body rises to the danger level, which surpasses 50 V.

The earth (ground) cable surrounding the installation that the ELCB is protecting is used to detect fault currents from phase. If the ELCB sensor coil detects a significant voltage, power will be cut off and remain off until the circuit breaker is manually reset.

The fault currents from a phase to any other earthed body are not sensed by a voltage sensing ELCB. Read also: https://elcb.net/

These ELCBs keep an eye on the voltage on the ground wire and cut the power if it rises beyond 50 volts.

Any other parallel piles of earth in the vicinity must not be put within the resistance zone of the earth electrode.

2 Current Earth Leakage Circuit Breaker

The present ELCB is a widely used circuit breaker. Additionally known as RCCB (Residual Current Circuit Breaker)

Purpose of Operation

A three-winding transformer with two primary windings and one secondary winding makes up the Current ELCB (or RCCB)The Core Balance Current Transformer is what it is named (CBCT).

The two principal windings are the phase and neutral wires. The second winding is a wire-wound coil.

When the system is balanced, there is no current flowing through the secondary winding. For instance, if the phase wire is carrying 5 A, then the neutral wire will likewise get 5 A of current.

The current’s sum is zero. In this state, the present ELCB is not operated, which is the regular status. When a person touches a phase wire, current flows from the phase to the earth.

A 5A (normal load) + 30 mA fault current is carried by phase right now. But a 5A current travels through our neutral wire.

There is a 30mA current differential. The CBCT (Core Balanced Current Transformer) detects it and sends the information to the relay operating coils.

A little quantity of current will also flow to the ground when a fault happens. As a result, the phase and neutral currents are out of balance, which throws the magnetic field out of equilibrium.

The secondary winding, which is attached to the sensing circuit, experiences an induced current as a result. This will identify fault currents, alert the system that trips the contact, and detect the fault currents.

What is the purpose of ELCB?

The principal reason for ELCB is to identify Earth spillages and keep injury to people from electrical shocks and forestall electrical flames that are brought about by hamper.

How does ELCB WORK?

An ELCB is a particular kind of locking transfer that has a structure’s approaching mains power associated through its exchanging contacts so the ELCB disengages the power in an earth spillage (dangerous) condition. The ELCB distinguishes shortcoming flows from live (hot) to the earth (ground) wire inside the establishment it secures. Assuming high voltage shows up across the ELCB’s sense loop, it will turn off the power, and stay off until physically reset. Hence, safeguarding the electrical framework in the structure


  • Voltage-operated ELCBs have fewer annoyance trips because they are less sensitive to fault situations.
  • Faults that don’t transmit electricity to the earth rod via the circuit protection conductor (CPC) are not detected by them.
  • Parallel earth has no impact on an ELCB that is currently operating.
  • This gadget is not susceptible to errors.
  • It is affordable and effective.
  • Both humans and animals are shielded from electrical shock by it.
  • When the installation has two connections to the earth, this process will result in a voltage gradient in the soil that will provide the ELCB sense coil with enough voltage to cause it to trip.


  • failure to act in specific circumstances.
  • For load protection, an ELCB needs a reliable ground connection.
  • Trips for bother.
  • Water heaters, washing machines, coolers, and other electrically faulty appliances could trip the CKL.
  • They might trip in response to an external voltage coming from a metal pipe or other object linked to the earthling system.
  • If a problem doesn’t send electricity through the CPC to the earth rod, they cannot find it.
  • Because the earthling system is attached to the pipes, they do not make it possible to readily divide a single building system into different sections with independent fault protection.
  • A high earth leakage current from other buildings may raise the local ground potential if the electrical installation earth rod is placed close to another earth of a building. This will result in a voltage difference across the two earths, which will trip the ELCB once more.
  • ELCBs offer extra resistance and a second point of failure to a voltage that is high enough to trip the device.
  • A TN-S earth, TN-C-S combined neutral and earth, or external voltage from something connected to the earthling system, such as metal pipes, may trip them.


With an automatic shut off when leakage is detected, earth leakage circuit breakers are used in applications to prevent electrical shock and electrical fires that arecaused by a control panel overload or short circuit.

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Zaman Lashari
Zaman Lashari
Articles: 701

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