Everything you need to know about MCBs

When we talk about electrical devices, we think about safety. MCBs are extremely helpful in preventing excessive current flow across an electrical circuit.

They break the circuit whenever the need arises. In other words, they act like a fuse in the case of short circuits.

MCBs are widely popular and used in every office building and residence. They are the most vital component of an electrical system that ensures safety against fire hazards.

What are MCBs?

MCBs stands for Miniature Circuit Breakers. They are electrical switches that operate automatically. As the name suggests, MCB’s work is to break a circuit when an excessive current flows through it. They protect the electrical circuit from overloading and short-circuiting. MCBs ensure protection from damage to any electrical circuit. 

Working principle of MCBs:

The working principle of an MCB is like a fuse. Miniature Circuit Breakers provide overcurrent protection to electrical circuits.

MCBs act as soon as current overflows. All MCBs have bimetallic strips that respond immediately to excessive current flow. As the current exceeds the safety limit, the strip bends. This opens up a latch to break the circuit. It stops the current flow.

In this way, MCBs provide overcurrent protection to electrical appliances.

Components of MCBs:

Miniature Current Breakers have the following parts.

  1. Frame:

The frame forms an outer case of the circuit breaker. It is rigid and hard to provide shock-proof protection to the MCBs.

  1. The operating mechanism: 

It is a switch with three parts. They are on, off and trip. In case of an overcurrent, switch trips. It goes to the “off” state when the power turns off.

  1. Trip Unit:
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The trip unit is the principal part of an MCB. The trip unit of an MCB reacts promptly to any overcurrent or short-circuit. This part consists of a bimetallic strip and an electromagnet.

  1. Contacts:

These are the contact points of circuit breakers that open up during an overcurrent. It immediately stops the current from flowing any further. The contacts are helpful in breaking the current flow. 

Types of MCBs:

There are five different types of MCBs. They are as follows.

  1. A type MCBs:

They are highly sensitive circuit breakers and useful in tripping off circuits that exceed the safety current limit by twice. They are used in semiconducting devices. 

  1. B type MCBs:

They help to trip current that is five times greater than the safety rating. B-type MCBs are popular for domestic applications.

  1. C type MCBs:

They come in handy when the current in the circuit exceeds the safety limit by ten times. C-type MCBs are for a high surge in current. They are used in industrial sectors. 

  1. D type MCBs: 

When the current exceeds the safety limit by more than ten times, D-type MCBs are helpful. They provide high resistance and are useful in welding equipment and large motors.

  1. K type MCBs: 

These are useful for heavy-duty loads like winding motors where the current reaches up to twelve times the recommended value.

Legrand has an extensive collection of all types of Miniature Circuit Breakers to shop from.