# 8 Difference Between ELCB and RCCB

### Difference Between ELCB and RCCB:

ELCB stands for Earth Leakage Circuit Breaker and RCCB stands for Residual Case Circuit Breaker. ELCB and RCCB is the most confusing terms in electrical. RCCB is an updated version of ELCB. Now a days ELCB is completely replaced by RCCB. In this article, We are going to see 5 Basic difference between ELCB and RCCB. Lets see..

### ELCB Earth Leakage Circuit Breaker:

Here You can see that, the green wire is called earth, and the earth terminal is connected through the sensing block. Take an example of that outgoing red color wire accidentally have a contact with the green color wire, then there is a leakage of current flows between the phase wire and green ground wire. Due to this, there is an voltage drop developed across the tripping coil. This voltage drop is enough to activate the trip circuit. Hence Finally ELCB open or isolate the source from the fault.

### RCCB Residual Current Circuit Breaker:

RCCB is working under the principle of Core balance Current Transformer. The RCCB monitors the how much current flows in the phase wire and neutral wire. Generally the load will be connected across phase and neutral terminal. Here the RCCB’s CBCT,monitors the vector sum of phase current and neutral current, because of how much current in the phase wire should return through the neutral wire.

i.e if phase wire carry 20Amps means, obviously the same current 20 Amps will be returned in the neutral wire also. Therefore the vector sum in the CBCT will be Zero. Then RCCB does not operate under Normal condition. Now consider a fault or a living human touches the live phase wire, which causes the leakage current flows between the live wire to Earth. Now phase carries 20Amps (Existing load) + 30 mAmps (Fault current or Leakage current), but Our neutral wire carries 20Amps because of the leakage current have anothor path of Earth (see In the picture green wire). Since the difference of 30 mA will be sensed by our RCCB’s CBCT. The CBCT sends this unbalance current to the relay operating coils. Finally RCCB trips or Isolate the circuit from the fault.
Note: Here the legend ‘Trip coil’ means magnetic trip arrangement