PPT.ppt (Size: 1.21 MB / Downloads: 173)
Residual current circuit breaker
World’s first protective system is developed in South Africa by Henri Rubin.
High sensitive earth leakage protective system
Name of that was MAGAMP.
It was second harmonic magnetic amplifier core balance system.
Operated at 525 V and 250 mA.
RCCB is the circuit breaker that senses the fault current and trips when there is a difference between amount of current in line and neutral.
Various names of RCCB and specifications
As per NEC various rating of RCCB
China is only the manufacturer in the world.
Cost ranging from 1000 to 5 lacks and more.
Used as household appliance and in transmission line.
As per characteristic
1. Type A
Residual sinusoidal current
Pulsating direct current
Independent of polarity
2. Type AC
Only residual sinusoidal current
3. Type B
As for type A
Residual current up to 1000 Hz
3. Reset button (when pressed 4 & 5 get closed)
6. Sense coil
7. Sense circuitry (picked up because of differential current)
8. Test button
9. Test wire
Number of poles
Two poles for single phase
Three poles for three phase three wire
Four poles for three phase four wire
According to maximum sustained load
As per IEC
High sensitivity (6-10-30 mA)
Medium sensitivity (100-500-1000 mA)
Low sensitivity (3-10-30 A)
Alone RCCB can not protect overload and short circuit. For that RCCB with overload & short circuit protection must be provided.
Household RCCB can not protect a person who touches live and neutral contact.
Tripping of RCCB is nuisance for earth fault.
To avoid such condition RCCB is available in 1, 2, 3, 4 pole.
RCCB acts like a fuse in transmission line. it senses and trips the faulty line from the rest of the healthy line.
The cost of one RCCB is less than the cost of relay unit and circuit breaker unit so RCCB is more economical than the unit of relay and circuit breaker.
It occupies less space.
For different types of the faults one RCCB is required so system is became more compact.
The TOP of RCCB is less.