MCCBs and MCBs are two things that appear similar but have significant differences. Both are designed to protect electrical circuits by automatically shutting down power during electrical faults, but their usage varies based on factors like capacity, mechanisms and applications. This blog breaks down the MCB and MCCB difference. Read on to find out.
Miniature Circuit Breaker
The MCB is an automatic electrical device used to protect circuits from damage caused by increased current, such as overloads or short circuits. With a simple working principle, the MCB features movable and fixed contacts. When the current exceeds the limit set, these contacts disconnect, interrupting the circuit and preventing any possible damage. This essential element ensures electrical systems’ safety whenever problems are detected by disturbing current flow and keeping equipment from threats.
Working
Here is how MCBs work:
- They primarily function to protect the equipment from passing overcurrent.
- MCB consists of one fixed and one movable contact.
- The movable contacts are disconnected from the fixed contacts when the current exceeds its set limit, which makes the circuits open and disconnects them from the main supply.
Examples
- MCBs are mostly used to protect home and commercial property appliances and devices. These include air conditioners, refrigerators, etc.
- Electrical distribution boards also use MCBs to protect lighting and socket circuits.
- Renewable energy systems like solar PV systems use MCBs for protecting DC circuits from short circuits.
Molded case circuit breaker
A Moulded Case Circuit Breaker (MCCB) is a device used to protect circuits from overloading that can be adjusted to suit high-current applications. In contrast to the MCB, it includes a manually operated contact for tripping. It has a bimetallic contact that has two arrangements, i.e., one for over-temperature and the other for over-current.
This contact expands and contracts with temperature changes. In normal conditions, it allows current flow, but if it exceeds predefined limits, the contacts expand until they open, disconnecting the circuit. This crucial feature shields equipment from potential damage due to excessive current.
Working
Here is how MCCBs work:
- MCCBs possess two types of arrangement, one for over-temperature and the other for over-current.
- MCCB contain bimetallic contacts that expand and contract because of the changing temperatures.
- When opened, the contact usually allows the current to flow through the circuit.
- Once the current exceeds the defined limit, the contacts heat up until they disconnect. The MCCB disconnects the circuit from the main supply and protects the equipment from damage.
Examples
- You can find them in industrial applications, such as manufacturing plants, refineries, power generation facilities, and more.
- Likewise, commercial buildings, including hospitals and malls, also use MCCB to protect electrical systems against overcurrent and short circuits.
Main Difference Between MCCB and MCB
The following are the main difference MCB and MCCB
| Features | MCB | MCCB |
| Purpose | Protects small electrical circuits from overload and short circuits. | Protects against overloads, short circuits, and ground faults in larger systems. |
| Current Rating | It can handle up to 125A (Amperes). | It can handle up to 2500A. |
| Voltage Range | Works with low-voltage circuits (below 415V). | Used for medium-voltage and high-voltage circuits (up to 1000V). |
| Breaking Capacity | Handles faults up to 10kA, meaning it can stop smaller power surges. | It can break currents from 10kA to 100kA and is useful for high-energy systems. |
| Trip Mechanism | Uses a thermal-magnetic mechanism to trip the circuit in case of overload. | Uses thermal-magnetic and electronic trip units for advanced protection. |
| Adjustability | Fixed settings – Cannot be adjusted to change sensitivity. | Adjustable settings – Allows tuning of the trip sensitivity based on load needs. |
| Size & Build | Small, compact, and lightweight, designed for home and office use. | Larger and bulkier, built for industrial and commercial applications. |
| Resetting After Trip | It can be manually reset easily after tripping. | It can be reset but may require maintenance or inspection after tripping. |
| Response Time | Faster tripping for overload protection in smaller circuits. | Slower tripping, designed to handle high inrush currents in industries. |
| Applications | Ideal for homes, offices, shops, and small commercial setups. | Used in factories, power plants, malls, hospitals, and large industrial setups. |
| Installation | Mounted on DIN rail inside distribution boxes. | Installed in separate electrical panels due to its large size. |
| Cost | Cheaper, as it serves low-power applications. | More expensive, due to its high capacity and advanced protection. |
| Lifespan & Durability | Has a long lifespan when used for household applications. | More rugged and durable, made to withstand industrial conditions. |
| Maintenance | It is low maintenance, as it’s designed for simpler circuits. | It requires regular maintenance for proper industrial functioning. |
Summing Up
To sum up, MCCBs and MCBs are both equally essential components in any electrical system. The ideal one is decided based on the requirements of the application. If you are looking for a compact, cost-effective solution for your household needs, MCBs are the right choice for you. On the other hand, if you need high-capacity protection for your industrial needs, MCCBs are the best fit. Now that you know the difference between MCB and MCCB, make the right choice from L&T Suffin. Explore the different MCB and MCCB according to your needs and avoid the worries of short circuits and overloads in your life.
FAQ’s
Why is MCCB important?
MCCB helps prevent overloads and short circuits in electrical systems. It is used in industries and commercial buildings like hospitals, malls, etc.
What is a MCCB used for?
An MCCB is used to ensure the electrical safety of applications used in industrial setups, manufacturing plants, and refineries.
What is the use of an MCB?
MCBs are used to protect DC circuits from overloading and short circuits. You can find them in residential and commercial buildings to safeguard appliances from heavy damage.
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