Types of Circuit Breakers: How to Classify Circuit Breaker?

Types of Circuit Breakers

Circuit Breakers are mechanical switching devices that can make, break, or carry a circuit manually or automatically under normal and abnormal conditions. 

The Circuit Breaker is described in short as CB.; The characteristics of a Circuit Breaker are as follows:

A Circuit Breaker can make or break an electrical circuit under normal operating conditions, either manually or using a remote control.

Under abnormal or fault conditions, a Circuit Breaker can break the circuit automatically.

The Circuit Breaker can make the circuit under fault conditions either manually or using a remote control.

Under normal conditions, a circuit breaker can make, carry, or break currents, and under abnormal conditions, it can make or carry for a specific time and break the winds.

Common Types of Circuit Breakers

A Circuit Breaker contains two elements - 

• a thermal part that reacts to moderate overloads;
• a magnetic part that reacts to short circuits.

Basic types of the circuit breaker, or MCB, or Miniature Circuit Breaker, you may find as below:

Type B

Trips between 3x and 5x the rated current.

For example - a 10A circuit breaker would need between 30A and 50A before it trips.

Type C

Trips between 5x and 10x the rated current. For example, a 10A circuit breaker would need between 50A and 100A before it trips.

Type D

Trips between 10x and 20x the rated current. For example, a 10A circuit breaker would need between 100A and 200A before it trips.

Type K

Less common, this type of trip is between 10x and 14x the rated current. This is within the trip range of the D type.

Type Z

Another uncommon option is type Z trips between 2x and 3x rated current. This puts it below the trip range of type B.

You may read the details of Air Circuit Breaker and Oil Circuit Breaker.

ABB, MCB (Miniature Circuit Breaker) Types and section conditions:

Electrical Substation Equipment: Circuit Breaker and Its Functions

Circuit Breaker Classification by voltage and application

• Low-voltage (LV) breakers — used in homes, commercial buildings, and small distribution panels.

• Medium voltage (MV) breakers — used in industrial plants and utility substations for distribution-level protection.

• High voltage (HV) breakers — used on transmission systems and large substations for power-grid switching and protection.

Circuit Breaker Classification by arc-quenching medium

• Air circuit breaker (ACB) — uses air as the interrupting medium; common in low-voltage switchgear.

• Vacuum circuit breaker (VCB) — extinguishes the arc in a vacuum; fast operation and low maintenance for medium-voltage applications.

• SF6 circuit breaker — uses sulfur hexafluoride gas for excellent arc quenching in medium and high voltages.

• Oil circuit breaker — uses insulating oil to quench the arc; historically common in high-voltage equipment but less used today.

• Air-blast circuit breaker — uses compressed air to blow out the arc; applied in some high-voltage systems.

Circuit Breaker Classification by construction and mounting

• Miniature circuit breakers (MCB) — compact thermal-magnetic devices for low-current residential and light commercial circuits.

• Molded case circuit breakers (MCCB) — larger, adjustable trip settings for industrial and larger commercial loads.

• Residual current circuit breakers (RCCB / RCD / GFCI) — detect imbalance between live and neutral to protect against earth leakage and electric shock.

• Earth leakage circuit breakers with overcurrent (RCBO) — combine overcurrent and earth-leakage protection in one device.

• Switchgear-mounted breakers — integrated into panelboards or switchgear assemblies for distribution and protection.

Circuit Breaker Classification by operating mechanism and features

• Thermal-magnetic breakers — use a bimetallic strip for overload (thermal) and an electromagnet for short-circuit trips (magnetic).

• Electronic/digital trip breakers — use digital electronics for precise protection, metering, communications, and programmable trip curves.

• Hydraulic-magnetic breakers — use fluid damping with a magnetic trip for stable performance under vibration and temperature changes.

• Manual vs. automatic breakers — manual breakers require operator switching; automatic breakers trip on fault and can be motor-operated for remote control.

Circuit Breaker Quick selection guidance

• Residential: MCBs for branch circuits, RCCB/GFCI for personal protection, MCCB for main service.

• Industrial: MCCB or molded-case for feeders; VCB, SF6, or vacuum breakers for MV switchgear; digital trip units for protection coordination.

• Utility/transmission: SF6, vacuum, or specialized HV breakers rated for high interrupting capacity and system voltage.

A circuit breaker is a protective device that automatically interrupts electrical flow when an abnormal condition, such as overload or short circuit, occurs, preventing equipment damage and fire.