Residual Current Circuit Breaker
What is Residual current circuit breaker ( RCCB )?
This device is very important in electrical wiring.It is a life guard device to protect from electric shock.Others circuit breaker only can detect the fault from over current and short circuit but cannot detect the current leakage.
That why RCCB is very important.Only this device can detect the current leakage.The current leakage can cause the injury or dead for human and can lead to fire hazard.When design the distribution panel board,please make sure this device include in our planning to install..it for consumer safety and avoid equipment from damage.
The main purpose for RCCB is a provide protection against direct and indirect contact of personnel or livestock and probable fire.Prevents shocks caused by earth leakage which could be fatal.
Principle of operation
How RCCB can detect the current leakage?Ok..it use the simple theory of balance current through the current transformer.The residual current device monitor the different between the load flowing through the current transformer and ensure the value of ampere is approximately zero.
If current leakage happen,the current flow will not in zero value,the different value exceed the rccb current rating,it can make the current transformer energized and send the signal to the plunger to cut off the breaker.The important thing to ensure this device operate properly,the earthing cable must be installed in electrical wiring.If not,RCCB cannot detect the current leakage cause the current is floating in circuit.
Protection against electric shock
1) protection in the case of indirect touch (indirect protection of persons) and fault protection when disconnecting impermissibly high touch voltages caused by short-circuit to exposed conductive parts.
2) protection in the case of direct touch (direct protection of persons) – disconnection as additional protection where live conductors are touched directly.Hazardous shock currents are disconnected within no time if the rated residual current of the device is In – 30 mA.
3) protection against electrically ignited fire (fire protection) – if the rated residual current of the device is In – 300 mA
General Description Of RCCB
- To open a circuit automatically in the event of an earth leakage between phase and earth and/or neutral and earth. With effective protection against human contact to earth points.
- Protection against Direct Contact of persons or livestock with live part.
- Protection against Indirect Contact of persons or livestock with exposed conductive parts which have become live under fault conditions.
- Protection against Electrical Fires caused by high resistance fault arching but not causing the over current protection device to operate.
- Designed with surge current withstand capability to prevent nuisance tripping during thunderstorms. Conditionally surge current proof (250A, 8/20us), without time delayed tripping.
- These devices are sometimes called an ELCB or RCD.
- Use in domestic, commercial and industrial installations.
RCCB Sensitivity
1) 30mA ( mili ampere )
- Tripping current designed for additional protection against direct contact, or where specially required by wiring regulations, the 30 mA RCCB protects against leakage currents and indirect contact with earth loop impedance up to 1667 Ohms; for use as additional protection against direct contact, residual tripping current must not exceed 30 mA.
2) 100mA ( mili ampere )
- Tripping current is suitable for protection against indirect contact and leakage currents for larger installations; the 100 mA RCCB’s operate within 30 ms, but do not provide the same level of personal protection as the 30 mA units; the 100 mA RCCB protects against leakage currents and indirect contact with earth loop impedance up to 500 ohms.
3) 300mA ( mili ampere )
- A less sensitive protection suitable for large installations having high levels of leakage current; 300 mA RCCB’s protect against leakage current and indirect contact up to 167 ohms earth loop impedance.
RCCB possible application area
1) For universal use in normal circuits
2) For additional protection of socket outlet circuits
3) To achieve a high degree of service security
4) For commercial and industrial power installations
RCCB wiring technique
