Difference Between ELCB, RCB and RCD Circuit Breakers
ELCB stands for “Earth Leakage Circuit Breaker” and it is used for protecting a person from electric shock and injury. The needs of these devices arise because of the number increasing in injuries as well as deaths because of electric shock. This device is invented almost 50 years ago, but nowadays ELCB is not suitable because of its some disadvantages hence another device RCB (Residual circuit breaker) or RCD (Residual Current Devices) whose functionality is same with more advantages, but theory of operation is entirely different from ELCB.
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Disadvantages of ELCB:
- Without proper earth connection, ELCB will not work. If the wire attached to the earthed rode is loose or broken, then ELCB would not able to sense the potential hazardous voltage on the metallic body of the electrical/electronic device.
- ELCB is attached between earthed wire and metallic body of the electrical appliances. But there are many other parallel paths for the currents to flow from the connected device body to earth without going through earthed wire. E.g. there are many metallic pipes in the house, which can provide a parallel path for the current to flow towards the earth. In this way, sometime ELCB is not able to detect the hazardous voltage on the metallic body of the device, which may cause serious injury.
- If someone gets in touch with live phase wire, ELCB will not Trip because in this case, there will be no current flow in the earth wire. In fact, current is flowing from the live wire to earth through the person’s body.
- When a live wire comes in contact with neutral wire, short circuit will occur, hence, ELCB will not trip because there will be no current in the earth wire.
- There are many cases in which, there is a current flow in the earth wire, but the situation is not hazardous in such cases, but it gives false trip e.g. lightening strike, current starts flowing in the earth wire and ELCB trips.