2. What is an ELCB?
• Earth Leakage Circuit Breakers are safety devices that provide
additional protection against earth leakage. ELCB is employed
in places where the earth impedance is high. The primary
objective of these devices is to reduce the risk of shock in the
event of a current flow to the earth.
• When energy “leaking” to earth is detected at a level detrimental
to a person using electrical equipment, an ELCB is an electrical
safety device specifically intended to immediately turn off the
current. Electric shock protection is provided by the ELCB.
3. Working Principle of ELCB:
The ELCB works on the principle that:
PRINCIPLE OF ELCB
They function by comparing the current flow in the:
•Active (supply) conductors and
•Neutral (return) conductors
of an electrical circuit on a continuous basis. When the
current flow in the Active conductor gets sufficiently
imbalanced, some of the current in the Active conductor
does not return through the Neutral conductor and leaks to
earth.
4. Construction of ELCB in a circuit:
• Every electrical device enclosure must be earthed, according to
international standards. As a result, there would be no risk of electrocution.
It is necessary to bury a metallic rod deep in the soil for proper operation of
an ELCB, and the ELCB is connected between the wire coming from the
rod and the wire attached to the external metallic body of the Electrical
device, or you can say that the ELCB is connected to the Earth wire.
• FLOW CHART OF ELCB
5. Operation of the ELCB in a circuit:
• When the live wire (unintentionally) comes
into contact with the metallic body of the
connected device or appliance, a potential
is created between the earthed rod
and the gadget’s metallic enclosure. The
circuitry (within the ELCB) detects the
potential difference and switches off the
main supply to the connected device when
the potential difference reaches 50 volts.
It safeguards the safety of human beings
in this manner.
6. Function of ELCB in a circuit:
•Phase, Neutral and Earth are connected
through ELCB.
•ELCB working is based on the earth leakage
current occurrence.
•The human body’s safest current limit is 30
milliamperes per second.
•Assume that the human body has a
resistance of 500 ohm and that the voltage to
ground is 230 volts.
•500/230=460mA will be the body current.
•As a result, the ELCB must be run at
30mA/460mA=0.65msec.
7. k
•Advantages of ELCB:
• ELCBs are used to protect against electrical shock and are designed to
function with a leakage current of less than 30 milliamps.
• ELCB has a 30ms operating time.
• Because of the leakage current, ELCBs are employed to defend against fire.
They are designed to operate when the current is less than 100mA.
8. Disadvantages of ELCB:
• If someone touches a live phase wire, the ELCB will not
trip since there will be no current flowing through the
earth wire. In actuality, current is travelling through the
person’s body from the live wire to the earth.
• When a live wire comes into touch with a neutral wire, a
short circuit occurs, and the ELCB does not trip since the
earth wire has no current.
• There are many situations when current flows through
the earth wire, but the condition is not dangerous; rather,
it causes a false trip, such as when lightning strikes
and current flows through the earth wire, causing the
ELCB to trip
9. Applications of ELCB:
•ELCB instantly breaks the circuit, preventing
damage to the associated circuits in residential
area and commercial buildings.
•ELCB’s are essential in moist areas where
there’s a higher chance of electrical shock.
