ELCB Wiring Diagram and Connection Procedure

ELCB means Earth Leakage Circuit Breaker. In this article, we are going to see the wiring diagram of different types of ELCBs and their connection procedure. ELCB is an electrical protective device that gives protection against leakage faults. A leakage current is an unwanted current flowing from the phase to earth through the grounding wire or other conductive path. Leakage current flows due to different types of faults and accidents so by detecting the leakage current we can prevent different types of faults. For example, due to insulation failure, the phase conductor may get a conductive path to the earth, and a leakage current starts flowing. Even when a person gets an electric shock then also a leakage current flows from the phase to earth through the person's body.

Leakage current faults can create unwanted heat in the circuit, cause electrical power loss, or make the system unbalanced so we must need to prevent the leakage current fault. Here, ELCB comes in the use. There are two types of ELCB - Voltage Operated ELCB and Current Operated ELCB(also known as RCCB). Anyway, let's see the wiring diagram for each of them.

Voltage Operated ELCB Wiring Diagram

Here, you can see the wiring diagram of the voltage-operated ELCB.

Voltage-operated ELCB is generally connected in series with the earth conductor. So when the leakage current flows through that earth conductor a voltage will be applied across the ELCB. Once the ELCB senses that voltage it disconnects the main power supply. We know that the metallic body of most of the electrical devices is connected to the Earth. Here, in the above wiring diagram, you can see the earthing wire from the body of the load is connected to the ELCB, and from the ELCB it is connected to the earth. So when the phase touches the body of the load accidentally, the leakage current will flow from the load to earth through the ELCB. And the ELCB will be got tripped so the load will immediately disconnect from the power supply. The voltage-operated ELCB has some disadvantages such as,

• It can not sense when a very low amount of leakage current flows because it cannot generate the appropriate voltage drop across the ELCB.
• It only gives protection when the leakage current flows through the earthing conductor if the leakage current flows through other paths (such as the human body during electric shock or phase conductor directly touches the earth).
• It needs an additional connection for earthing.

Voltage Operated ELCB Connection Procedure

As I told you, the voltage-operated ELCB needs all the connections including earthing so its connection little different from the RCCB. Here, a single-phase ELCb is shown in the above wiring diagram, for the three-phase also the same just we need to connect additional wires to the incoming and outgoing.  Flow the below connection procedure,

• Connect the power terminals from the power source to the incoming side of the ELCB. Here phase and neutral are connected. If you a three-phase three-wire system then connect all three phases R, Y, and B, or if you use a three-phase four-wire system connect all three phases and neutral.
• Connect the outgoing power terminals to the load circuit.
• Connect the earth terminal of the load circuit to the input earthing terminal of the ELCB. The earthing wire may come to form a single load or the whole electrical system in the building.
• Connect the output earthing terminal of the ELCB to the earth by proper earthing.

Current Operated ELCB Wiring Diagram

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

The current-operated ELCB detects the leakage fault by measuring the unbalance current in current-carrying conductors such as between phase and neutral for a single-phase system and between three phases for a three-phase system. Current-operated ELCB has an arrangement and a sensing coil that continuously monitors the current flow through the conductors. In normal conditions, when there is no leakage fault, both the phase and neutral conduct an equal current but when a leakage fault occurs the phase and neutral will conduct an unequal current and this unbalanced current will be sensed by the sensing coil of the ELCB and it will trip the circuit. You can see in the above wiring diagram there is no need for an earthing connection for the current operated ELCB. Also, it has so many advantages over the voltage-operated ELCB such as,

• It can sense the leakage current fault happens anywhere in the circuit.
• It can give protection against electrical shock.
• The sensitivity is higher, it can sense a very low amount of leakage current.

Current Operated ELCB Connection Procedure

As I told you there is no need for an earthing connection so just follow the below procedure,

• First, find out the incoming and outgoing terminals, it is already written on the device.
• Connect the power source terminal to the incoming side.
• Connect the outgoing terminal to the load circuit.

4 Pole ELCB Connection and Wiring Diagram

4 pole ELCB is used for a three-phase four-wire system where all three phases and neutral are to be connected. Here, you can see the incoming and outgoing connections of a 4-pole ELCB. Remember that it is a current-operated ELCB so we do not need any earthing connection for it.

Read Also: 

• [Proper] MCCB Connection Diagram and Wiring
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• Voltage Protection Device Wiring Diagram and Connection Procedure

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