MCB (Miniature Circuit Breakers)

 

Introduction of MCB

MCBs, or “Miniature Circuit Breakers,” should be installed in place of fuses for improved safety and control. Instead of a fuse, an MCB acts as an automated switch that opens if an excessive amount of current enters a circuit. As a result, a manual replacement is not required once the circuit returns to normal.

Most circuits use MCBs instead of fuse switches. MCBs are used in all types of home, commercial, and industrial applications today. Their breaking capacities range from 10 KA to 16 KA. Protection from these MCBs is dependable.

What is Miniature Circuit Breaker (MCB)?

MCB (Miniature Circuit Board) is a safety device with significant applications in both commercial and residential areas. This device is an electro-mechanical circuit protection device. Through an automatic safety mechanism, it prevents electrical circuits from being damaged by excessive current flow.
The MCB operates automatically, which means that if a short circuit or overcurrent occurs, the MCB will trip, interrupting the power supply and preventing any damages from occurring. Despite this, these devices are sensitive to even the smallest variations in current and can detect minute levels above the safety limit. An MCB interrupts a circuit when it is overloaded or shorted.

An MCB can be used as a substitute for a fuse in household applications. Over-fuses for MCBs have the advantage of being reusable even after an overload, or short circuit interrupts the circuit.

A Miniature Circuit Breaker (MCB) is a device that uses an electromagnetic device encased in a molded insulation enclosure. Its primary function is to switch the circuit, which means that it opens the circuit (connected to it) if the current passing through it (MCB) exceeds its setting. Like a normal switch, it can be manually turned on and off.

MCBs operate based on the overcurrent magnitude, determining how long they are active. As a result, they are operated whenever overloads are present for a long enough period to threaten the circuits they protect.

In this way, MCBs are not affected by transient loads such as surges in switch currents and motor starting currents. In addition, these devices are designed to handle short circuits within 2.5 milliseconds and overloads within 2 seconds to 2 minutes, depending on the current level.
In addition to single-pole MCBs, double-pole MCBs, three-pole MCBs, and four-pole MCBs are produced in various pole arrangements with different fault current levels.

In most cases, MCBs are linked into two-pole and three-pole versions, which ensure complete circuit isolation in case of a fault on one line. This feature will benefit three-phase motor protection with single phasing.

They are rated for DC supply at 220V and AC supply at 240/415V (single and three-phase) with different short-circuit current capacities. Single-phase devices can typically handle 100 A current loads. In some MCBs, the tripping current capacity can be adjusted; in others, it cannot since the load current or short circuit rating is fixed.

In addition to performing local control functions, MCBs are used to isolate switches from faults and provide overload protection for installations and equipment. Learn more