Miniature Circuit Breaker (MCBs) - A Guide

 

From what is an electrical MCB to how it works to what are different types of MCBs – this guide covers all the basic knowledge you need to have about Miniature Circuit Breakers.

What are MCBs?

MCBs are electrical switches that are automatically operated. A miniature circuit breaker is intended to provide safety to an electrical circuit when it gets excess current. This switch is designed for tripping while a short circuit or an overload takes place. Therefore, it prevents equipment failure and electrical faults.

MCB is extensively used as an isolating component in domestic, industrial, and commercial settings. They are part of a much broader pack of circuit-breaking components that have more power.

How Do Miniature Circuit Breakers Work?

The miniature circuit breakers get triggered with over current. This happens whenever the electrical current exceeds a pre-designated safe current limit. So, MCBs make use of a comparatively robust mechanical mechanism that is specifically designed for minimising failures and fake alarms.

The excess current heats the bimetallic strip in the MCB, and therefore, it bends and trips. This releases the electrical switch and further moves the electrical contacting points apart. This process ends up confining the arc and electrical discharge happens. The arc is then divided and thus, it cools down with the help of a metal strip. This insulated metal strip is known as the arc chute.

MCBs are designed to prevent both short-circuiting and overloading. These get detected separately by using different processes. The protection from overload is provided via thermal operation by the bimetallic strip. Whereas, the protection from short-circuit is provided with an electromagnetic operation by the tripping coil.

Different Electrical MCB Types

There are many types of MCBs, namely, MBC types A, B, C, D, K, and Z. However, MCBs of three types are most popularly used. These versions of MCBs are called type B, type C, and type D.

Here are how you can understand which of these three an MCB is:

Type B MCBs

A Type B MCB is designed for tripping if the flowing current hits between three to five times the fixated maximum or in simple words ‘rated load’.

Which is the most sensitive MCB type of all types? Type B. These MCBs designed for domestic applications. Also, they are used for a low voltage commercial setting where current surges are most likely to be acute.

Type C MCBs

A Type C MCB is used for furthermore powerful electrically operated devices where surges are mostly higher. These are generally used in industrial and commercial environments.

Type D MCBs

A Type D MCB is the least sensitive of all types. They only activate when surges are among ten to twenty times the rated load.

A D-rated MCB is built for heavyweight industrial and commercial devices where the current surges are very strong occasionally. For example, welding equipment, X-ray machine, large motor, and consistent power supply unit.

Dewas Metal Sections Ltd. are a leading manufacturer and supplier of cold roll formed metal sections. They are known to provide high-quality MCBs and other electrical components to various industries.