08/03/2025
Types of Circuit Breakers and Their Applications
1. MCB (Miniature Circuit Breaker)
MCBs are commonly used in residential and commercial electrical systems for the protection of low-voltage circuits. They provide automatic disconnection in the event of an overload or short circuit. Unlike fuses, MCBs can be reset after tripping. They are generally rated for currents up to 125A.
2. ELCB (Earth Leakage Circuit Breaker)
ECLBs are designed to detect earth faults and leakage currents. They protect against electric shocks and prevent fire hazards caused by insulation failure. These breakers are particularly useful in environments where electrical safety is a priority, such as homes, hospitals, and industries handling sensitive equipment.
3. RCCB (Residual Current Circuit Breaker)
RCCBs are used to detect and disconnect electrical circuits when there is a leakage current exceeding a predetermined value. Unlike MCBs, which respond to overcurrent and short circuits, RCCBs specifically address residual currents that could lead to electrocution or fire. These devices are typically used in combination with MCBs for comprehensive circuit protection.
4. MCCB (Molded Case Circuit Breaker)
MCCBs are designed for higher current ratings and are typically used in industrial and commercial applications. They offer protection against overloads, short circuits, and under-voltage conditions. MCCBs are available in ratings ranging from 100A to several thousand amperes, making them suitable for large electrical installations.
5. ACB (Air Circuit Breaker)
Air Circuit Breakers use air as an arc extinguishing medium and are commonly used in high-power applications such as power distribution panels and industrial systems. They provide reliable protection for electrical equipment operating at low and medium voltages. ACBs are preferred for their ability to handle high currents and multiple operational cycles.
6. VCB (Vacuum Circuit Breaker)
Vacuum Circuit Breakers utilize vacuum as the arc quenching medium. They are primarily used in medium-voltage applications due to their high dielectric strength and ability to interrupt high fault currents. VCBs are known for their minimal maintenance requirements and long service life, making them suitable for substations, power plants, and large industrial facilities.
7. MOCB (Minimum Oil Circuit Breaker)
MOCBs use a small amount of insulating oil for arc extinguishing. These breakers are used in medium-voltage applications and offer good thermal stability and arc suppression properties. However, they require periodic maintenance due to oil degradation.
8. BOCB (Bulk Oil Circuit Breaker)
BOCBs utilize a large volume of oil both for insulation and arc extinction. These breakers are suitable for high-voltage applications and were widely used before the introduction of more advanced technologies such as vacuum and SF₆ circuit breakers. Although effective, they have largely been replaced due to concerns over fire hazards and maintenance requirements.
9. SF₆ Circuit Breaker (Sulfur Hexafluoride Circuit Breaker)
SF₆ circuit breakers use sulfur hexafluoride gas for arc extinction and insulation. They are highly efficient in high-voltage applications, offering excellent dielectric properties and thermal stability. SF₆ breakers are widely used in electrical grids, substations, and industrial power systems where reliability and efficiency are critical.
