A Complete Guide To Molded Case Circuit Breaker (MCCB)

What Is An MCCB?

A moulded case circuit breaker (MCCB) is a type of electrical protection device used to safeguard an electrical circuit from excessive current, resulting in overload or a short circuit. MCCBs, which have a current rating of up to 2500A and changeable trip settings, can be used for a wide range of voltages and frequencies. In large-scale PV systems, these breakers are utilised instead of tiny circuit breakers (MCBs) for system isolation and protection.

The key advantage of MCCBs is that we can customise them to meet our needs by introducing new features such as remote closure, UV trip, etc. It is the most cost-effective and functional replacement for an air circuit breaker.

How Does It Operate?

To offer the trip mechanism for protection and isolation, the MCCB combines a temperature-sensitive device (the thermal element) with a current sensitive electromagnetic device (the magnetic element). As a result, the MCCB can provide:

  • Overload Protection

The MCCB provides overload protection via the temperature-sensitive component. This component is essentially a bimetallic contact, consisting of two metals that expand at different rates when subjected to high temperatures. Under typical operating conditions, the bimetallic contact allows electric current to flow through the MCCB.

When the current reaches the trip value, the bimetallic contact begins to heat and bend away due to the contact’s differing thermal rate of heat expansion. The contact will eventually bend to the point where it physically pushes the trip bar and unlatches the contacts, causing the circuit to be stopped.

  • Electrical Fault Protection Against Short Circuit Currents

Based on the theory of electromagnetism, MCCBs give a rapid response to a short circuit problem. When current travels through the MCCB, a solenoid coil generates a modest electromagnetic field. The electromagnetic field generated by the solenoid coil is insignificant during normal operation.

However, when a short circuit defect occurs in the circuit, a huge current begins to flow through the solenoid, creating a strong electromagnetic field that attracts the trip bar and opens the contacts.

  • Disconnection Switch

MCCBs, in addition to tripping mechanisms, can be utilised as manual disconnect switches in the event of an emergency or maintenance operation. An arc can be formed when the contact opens, and MCCBs include inbuilt arc dissipation systems that quench the arc to combat this.

Types Of MCCBs

The MCCB is organised into five groups based on the types of trips.

Type B: They operate when the fault current reaches three to five times the full load current. It is employed in household applications such as resistive loads, lighting loads, etc. This beaker’s operation time ranges from 0.04 to 15 seconds.

Type C breaker is designed specifically for inductive loads such as transformers, welding equipment, electromagnets, etc. It operates with a time delay of 0.04 to 5 seconds and an operating range of 5 to 8 times the full load current.

Type D: Designed for high starting current applications such as motors, pumps, and elevators. It has a temporal duration of 0.04 to 3 seconds and an operational range of 10 to 15 times.

Type K: Operates when the current reaches 8 to 10 times its maximum load current. The operating time of a type K MCCB ranges from 0.04 to 5 seconds, and they are the most appropriate feeder protection.

Type Z: MCCBs are extremely sensitive and can allow 1.5 to 3 times the full load current. Type Z is appropriate for electronic loads when high-speed tripping is required.

IndoAsian provides a wide range of MCCBs ideal for residential and industrial applications. Our designs are the best in the business, and they are built to be long-lasting, safe, and simple to wire.

Visit our website at https://www.indoasian.com/ today to learn more about us!