What Sets MCB Apart from MCCB in Electrical Circuits?
MCB is the acronym used for the miniature circuit breaker and is commonly used in our day to day lives. Its primary function is to break the circuit when the current flowing through the circuit reaches past a certain set limit. In conditions such as short circuit or overload, these devices trip by themselves hence saving the house by the damages caused by a short circuit or overload or as the case may be. The mechanism of MCB has 3 possible positions, ‘ON’, ‘OFF’, and ‘TRIPPED’, hence the breaker provides manual means of opening and closing of the circuit. MCB is a kind of a better version of a fuse.
MCB Symbol
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MCB Electrical
MCBs work on a time-delay tripping mechanism. This means that they function whenever there is an overload or higher flow of current for a longer duration of time, the duration which can hamper the normal functioning of the circuit. The time duration if exceeds a certain value the MCB trips and breaks the circuit thus rendering the overload dysfunctional in damaging the appliances and further circuit.
What is MCCB?
MCCB is the short form for a moulded case circuit breaker. It is used to protect the electric circuit from the flowing of excessive current which can further cause damages such as overload and short circuit. They are being used for a wide range of frequencies with the current rating up to 2500A and adjustable trip settings. MCCB provides overload protection via the temperature-sensitive component. These are usually used in PV systems in place of miniature circuit breakers. These work on principles of electromagnetism and cam also be disconnected manually. MCCB’s are subjected to high current, therefore they need proper maintenance and can be maintained by regular cleaning, lubricating, and testing.
How is MCCB different from MCB?
Capacity
MCB’s trip characteristics may not be adjusted since they are mostly provided to low circuits with the MCB rated 100 amps with an interrupting rating of under 18000 amps. Whereas MCCB has the characteristics of the adjustable trip which is used in higher models. MCCBs provide amps between 2500-10 and their interrupting rating ranges from 10,000 amps to 200,00 amps. Hence this states that MCB is usually used for low energy requirements such as home wiring or small electric circuits, on the other hand, MCCB is more suited for high energy requirements.
Tripping Circuit
MCB being rated under 100 amps doesn't come with the feature of the adjustable trip, hence they always cater low current circuit. Whereas MCCBs being rated from 10 to 2500 amps comes with an adjustable trip feature so they can cater for high current circuits
Remote Feature
Although an MCCB possesses a higher capacity than an MCB, both are classified under low voltage circuit breakers and should respond to standards set by the IEC 947. For the sake of convenience, MCCB is equipped with a special feature of being tripped only by remote as their units have electrical motor operators. Whereas MCB lacks this feature.
Application
MCCB is said to be more suited for higher energy due to the possession of better capacity than MCB, whereas MCB is usually provided for low energy requirements, hence they are best suited for them.
Use
Obviously, when it comes to home use or some light work, the MCB is better preferred due to low energy requirements. On the other hand, when it comes to industrial use or any other heavy-duty requirements, MCCB is the best suited.
Difference Between MCB and MCCB.
Did You Know?!
The miniature circuit breaker was invented by Stotz-Kontakt, a company that was established in Mannheim, Germany, in the year 1891.
FAQs on MCB vs MCCB: Differences, Applications & Importance
1. What is the main difference between an MCB and an MCCB?
The main difference lies in their capacity and application. An MCB, or Miniature Circuit Breaker, is designed for lower current applications (typically under 100 Amperes) and is commonly used in residential and light commercial wiring. An MCCB, or Moulded Case Circuit Breaker, is built for higher current applications (from 100A up to 2500A) and is used in large industrial and commercial electrical systems. Additionally, MCCBs often feature adjustable trip settings, whereas MCBs have fixed settings.
2. What are the typical applications of MCBs and MCCBs?
The applications are distinct due to their current handling capabilities:
MCB (Miniature Circuit Breaker) Applications: These are primarily used for smaller electrical loads. You'll find them in home distribution boards for protecting circuits for lights, fans, home appliances (like refrigerators and microwaves), and in small office spaces.
MCCB (Moulded Case Circuit Breaker) Applications: These are used for heavy-duty protection in industrial settings. Common applications include protecting large motors, capacitor banks, main power distribution boards, and heavy machinery that draw significant current.
3. How is an MCB a better protective device than a traditional fuse?
An MCB offers several key advantages over a fuse:
Reusability: An MCB is a switch that simply trips (switches off) during an overload or short circuit and can be reset manually. A fuse contains a wire that melts and breaks the circuit, requiring a complete replacement.
Sensitivity: MCBs are more sensitive to changes in current and can react faster to overcurrent conditions, offering better protection to appliances.
Safety: Operating an MCB is safer as its internal mechanism is enclosed. Replacing a fuse can expose a person to live electrical parts.
Easier Fault Detection: A tripped MCB is easily identified by the position of its switch, whereas a blown fuse needs to be inspected to confirm.
4. What is meant by the 'interrupting rating' of a circuit breaker?
The interrupting rating (or breaking capacity) is the maximum fault current that a circuit breaker can safely interrupt without being damaged. This is a crucial safety parameter. MCCBs have a much higher interrupting rating (e.g., 10,000 to 200,000 Amperes) compared to MCBs (typically up to 18,000 Amperes), which is why MCCBs are used in high-power industrial systems where fault currents can be extremely large.
5. Can you use an MCCB in a home electrical panel instead of an MCB?
No, it is highly impractical and unsafe to use an MCCB in a typical home electrical panel. MCCBs are physically much larger and will not fit in a standard residential distribution board. More importantly, they are designed for much higher trip currents. Even the lowest setting on an MCCB might be too high to protect household wiring and appliances, creating a significant fire hazard in case of a fault.
6. Why do MCCBs have adjustable trip settings while MCBs do not?
MCCBs have adjustable trip settings because they are used in complex industrial environments with diverse and variable loads. This adjustability allows engineers to precisely coordinate the protection scheme, ensuring that only the breaker closest to the fault trips, a concept known as selectivity. MCBs are used in simpler, standardised residential circuits where loads are predictable (e.g., lighting, small appliances), so a fixed, pre-calibrated trip setting is sufficient and more cost-effective.
7. How does an MCB differ from an RCCB?
While both are safety devices, they protect against different types of electrical faults. An MCB (Miniature Circuit Breaker) provides protection against overcurrents—which includes both overloads and short circuits. An RCCB (Residual Current Circuit Breaker), on the other hand, provides protection against earth leakage currents. It detects small, dangerous currents leaking to the ground, which could happen if a person touches a live wire, and quickly disconnects the power to prevent electric shock. An MCB cannot detect such small leakage currents.
