The circuit breaker is a switching device that also offers protection by tripping & cutting off the supply to load in case of fault.
Primarily the circuit breakers are used for switching different kinds of load in Industries, Buildings, Commercial Complexes, Hotels, etc.
Need of a circuit breaker
Many kinds of abnormal conditions are there that exist in the electrical system, which have the potential to damage the circuit & its components. These conditions are defined as ‘FAULTS’. Further, the fault is categorized as mentioned below:
- Overload
- Short Circuit
- Earth
types of circuit breakers
Circuit breakers mainly are categorized based on application as per voltage:
1) Low Voltage Circuit Breaker
- MCCB
- ACB
- MCB
- RCCB
2) Medium Voltage Circuit Breakers
3) SF6/VACUUM Circuit Breakers
4) High Voltage Circuit Breakers
- VCB
- SF6
- OCB
- ABCB
circuit breakers at a glance
Low-voltage circuit breakers
Circuit Breakers operating for voltage up to 1KV are LV or Low Voltage Circuit Breakers which are as follows:
- MOLDED CASE CIRCUIT BREAKER (MCCB)
It is generally used for the current ratings up to 1600A & fault levels up to 150KA
MCCB or Molded Case Circuit Breaker is a kind of circuit breaker, which is enclosed in the molding or housing of a molded material & that is the reason it is known as Molded Case Circuit Breaker. It is generally used for the current ratings up to 1600A & fault levels up to 150KA.
- MINIATURE CIRCUIT BREAKER (MCB)
MCB or Miniature Circuit Breaker is a circuit breaker that is used for protection where current ratings are lower. It can be used up to 125A circuits & like MCCBs it also offers protection against overload & short circuits through bimetal & solenoid.
- AIR CIRCUIT BREAKER (ACB)
AIR CIRCUIT BREAKER or ACB as the name suggests it’s a circuit breaker where the medium of arc quenching is air. ACB is used for high-current applications and can offer protection against overload & short circuits up to 6300A.
- MOTOR PROTECTION CIRCUIT BREAKER (MPCB)
MPCBs are used especially for motor protection. MPCB as a standalone device offers protection against Overload, Short Circuits & Single Phasing, thus is used specifically for motor applications.
- RESIDUAL CURRENT CIRCUIT BREAKER (RCCB)
In case of current leakage, it senses the same & trips thus, saving the human & circuit
RCCBs as the name suggests offer protection against Earth Leakage. It is used in homes, offices & industries according to the current sensitivity required as per application. In case of current leakage, it senses the same & trips thus, saving the human & circuit from shock & adverse effects of current leakage.
Medium and high-voltage circuit breakers
Voltage level from 1KV-69KV is categorized under medium & 69KV-230KV is categorized as High Voltage. Circuit Breakers operating in these voltage ranges are known as Medium & High Voltage CBs respectively.
- VACUUM CIRCUIT BREAKER (VCB)
Vacuum Circuit Breaker or VCB is used for Medium Voltage applications. In VCB the contacts operation & arc quenching take place inside bottles where the Vacuum is present.
- OIL CIRCUIT BREAKER (OCB)
Oil Circuit Breakers were also used on high voltages & Oil was used as the arc quenching medium.
