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:

Difference between elcb and rccb

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:

Difference between elcb and rccb

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


Basis for Comparison ELCB RCCB
Definition Earth Leakage Circuit Breaker Residual Case Circuit Breaker
Construction ELCB consist of coil is connected in series with the earth point. When the phase touch on the Please the voltage will be developed in the earth conductor, hence the coil picks up the voltage. Then the ELCB trips the Circuit. Watch the Video..

It is also called as VOELCB (Voltage Operated Earth leakage Circuit Breaker)

RCCB is consist of Core Balance Current Transformer which is connected with the Trip coil. Under Normal Operating condition, the phase current is equal to Neutral current, since the vector sum of current in the CBCT is zero, therefore CBCT does not detect the current. Now consider Load have contact with the earth terminal means, there leakage current flows from phase to earth. This leakage current creates unbalance current in the CBCT. When the unbalance Current exceeds the preset value the RCCB disconnect the device….

It is also called as RCD (Residual Current Device)

Operation Voltage based operation are used in ELCB. Here the earth voltage will be deducted by trip coil. These devices measured the voltage on the earth conductor Current Based operation are used. The amount of current in the phase should return to the neutral. Flow of unbalance current will be deducted by the trip coil.
Installation All the earth should be grounded or connected in series through the Trip coil. The CBCT deducts the Residual current flow. Since It does not require all ground connection through the trip coil. Only output of the CBCT will be connected to the trip coil
Advantage Nowadays ELCBs are replaced by RCCB. Since ELCBs are very difficult to use and it has less operating range. All earth terminals cannot be rerouted through the tripping coil of the ELCB. Almost 95% of the home have RCCBs. Their performance is good. It used to protect the human under any electrical shock.
Cost Cost is high Less cost
Types AC => used for Alternating current AC => used for Alternating current
A => used for Square wave A => used for Square wave
B => Used to DC B => Used to DC
Earth connection It ensure the system is connected on perfect Earth which means ELCB sense the connectivity of earthing It does not monitor system earthing status. It monitors only the live and neutral
Earth connection ELCB have Connection in the earth wire.. RCCB will only have the line and neutral connections.
Nuisance Tripping Less High. Sudden changes in electrical load can cause a small, brief current flow to earth, especially in old appliances. RCDs are very sensitive and operate very quickly; they may well trip when the motor of an old freezer switches off. Some equipment is notoriously `leaky’, that is, generate a small, constant current flow to earth. Some types of computer equipment, and large television sets, are widely reported to cause problems.

Video Explanation of Difference Between RCCB and ELCB In English:

Video Explanation of Difference Between RCCB and ELCB In Tamil:

Video Explanation of Difference Between RCCB and ELCB In Hindi:

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