What are MCBs?

MCB stands for Miniature Circuit Breaker and refers to a type of electrical switch designed to automatically shut down electrical circuits in the event of a fault. MCBs are widely used to replace fuses across low-voltage electrical circuits because they are more dependable, sensitive, and easy to reset.

Types

MCBs are used as circuit breakers across industrial, commercial, and domestic applications. However, the types of MCBs often differ and the categorisation depends on the type of MCB, defining the tripping characteristics. As such, the types of MCBs are:

Type B

This type of MCB is characterised by instant tripping at a rate of 3 to 5 times the load current. They are ideal for use across residential and small commercial applications.

Type C

This type of MCB is characterised by tripping between 5 and 10 times the load current. They are ideal for industrial and commercial applications where high inductive loads are concerned.  

Type D

This type of MCB is characterised by tripping between 10 and 20 times and is typically used in applications where very high inductive loads are involved. That is why Type D MCBs have certain applications across industrial and commercial spaces, including welding equipment, winding motors, and x-ray machines.

Applications

MCBs are used widely as overload protection devices, load control switches, and isolating devices. They are critical for ensuring proper functioning and maintenance of electric machines, and hence, have applications in almost all electrical appliances, encompassing industrial, commercial, and residential applications. Some of the most common applications of MCBs include:

• In-home electrical panels to ensure equal and proper distribution of electricity across different devices, thereby preventing fluctuations. 
• In heaters to prevent high voltage fluctuations in home and office spaces.  
• In domestic and commercial lighting systems. 
• In small-scale and large-scale industrial applications, as in heavy machinery that requires up to 30 kA of power supply.