In the low-voltage power distribution system, MCB (Miniature Circuit Breaker) and Mould Case Circuit Breaker (MCCB) are both important protective components, but they have obvious differences in voltage adaptation, current capacity, application scenarios and other aspects. Understanding these differences is crucial for selecting the right circuit breaker for different power distribution needs. Zhejiang C&J Electrical co., ltd. (referred to as C&J Electrical) has in-depth research in the field of Mould Case Circuit Breaker, and its launched CJMM6RT series thermomagnetic molded case circuit breaker has excellent performance and wide adaptability, providing reliable protection for industrial and commercial power distribution systems.
Core Difference Between MCB and Moulded Case Circuit Breaker
MCBs: Generally used in lower-voltage commercial and industrial applications, typically 120V, 240V or 480VAC, and up to 1000 VDC. MCCBs: Can be used for both low and high-voltage applications, with ratings typically up to 600V or 690V, and some models rated for higher voltages. This is one of the most significant differences between the two. In addition to the voltage range, there are obvious gaps in rated current, breaking capacity, application scenarios and other aspects:
- Rated current: MCB has a smaller rated current range, usually 1-63A, which is suitable for small-current circuit protection; Mould Case Circuit Breaker has a larger rated current range, which can reach 16-1600A or even higher, and is suitable for large-current power distribution scenarios.
- Breaking capacity: The short-circuit breaking capacity of MCB is relatively low, generally 6-10kA; Mould Case Circuit Breaker has a stronger breaking capacity, up to 50kA or more, which can handle large short-circuit current faults more reliably.
- Adjustability: The protection parameters of MCB are mostly fixed and not adjustable; the Mould Case Circuit Breaker is usually equipped with adjustable thermal and magnetic release mechanisms, which can be flexibly set according to actual protection needs.
- Application scenarios: MCB is mainly used in household, small office and other small-power scenarios; Mould Case Circuit Breaker is widely used in industrial workshops, large commercial buildings, power distribution rooms and other large-power, complex power distribution systems.
Overview of Mould Case Circuit Breaker
Mould Case Circuit Breaker (MCCB) is a kind of low-voltage circuit breaker with a shell made of molded insulating material. It integrates functions such as power distribution, control and protection, and is mainly used to distribute electrical energy in power distribution systems, protect circuits and electrical equipment from overload, short circuit and other faults. Compared with MCB, Mould Case Circuit Breaker has the characteristics of large rated current, strong breaking capacity, adjustable protection parameters, and diverse installation methods. It can adapt to the complex working environment of industrial and commercial power distribution systems and ensure the safe and stable operation of the power grid.
According to the type of release, Mould Case Circuit Breaker can be divided into thermomagnetic type, electronic type and other types. Among them, the thermomagnetic type MCCB uses thermal and magnetic dual protection mechanisms, which has the advantages of simple structure, reliable performance and strong environmental adaptability, and is widely used in various industrial and commercial scenarios. C&J Electrical’s CJMM6RT series is a high-performance thermomagnetic Mould Case Circuit Breaker, which combines advanced technology and humanized design.
Core Functions of Mould Case Circuit Breaker
As the core component of the power distribution system, Mould Case Circuit Breaker undertakes multiple key functions, which are crucial to the safe and efficient operation of the power system:
- Power distribution function: Distribute the incoming main power to multiple branch circuits in a reasonable way to meet the power demand of different large-scale electrical equipment and production lines.
- Overload protection: Through the thermal release mechanism, when the circuit current exceeds the rated value for a long time, the bimetallic strip is heated and deformed to drive the breaker to trip, preventing the wire and equipment from being damaged due to overheating.
- Short circuit protection: Through the magnetic release mechanism, when a short circuit fault occurs, the instantaneous large current generates a strong magnetic field, which drives the tripping mechanism to act in milliseconds, quickly cutting off the circuit and avoiding serious accidents such as equipment burnout and electrical fires.
- Adjustable protection function: The thermal and magnetic protection parameters can be adjusted according to the actual working conditions of the circuit, improving the flexibility and applicability of protection.
- Circuit control function: It can realize the on-off control of the circuit manually or electrically, which is convenient for daily maintenance and emergency handling of the power system.
C&J Electrical’s CJMM6RT Series Mould Case Circuit Breaker: Core Advantages & Product Overview
C&J Electrical’s CJMM6RT series thermomagnetic Mould Case Circuit Breaker is a high-performance product designed for industrial and commercial power distribution scenarios. It is suitable for AC 50Hz with rated voltage up to 690V and rated current up to 1250A. It is generally used for power distribution, and circuit breakers with rated current below 630A can also be used as motor protection. Under normal circumstances, the circuit breaker can be used for the infrequent conversion of the line and the infrequent start of the motor. Its core advantages, structural features and technical parameters are as follows:
Core Structural Features & Advantages
- Low temperature rise: Adopts advanced heat dissipation structure and high-quality materials, which effectively reduces the temperature rise during operation, ensures stable performance and prolongs service life.
- Small volume: Optimized structural design, compact size, which saves installation space and is convenient for integration into various power distribution cabinets.
- Adjustable thermal protection: Equipped with thermal adjustable function (0.8-1.0 In), which can be flexibly set according to the actual load current, improving the accuracy of overload protection.
- Adjustable magnetic protection: Has magnetic adjustable function (5-10In), which can accurately respond to different short-circuit current levels and ensure reliable short-circuit protection.
- Multi-contact structure design: Adopts multi-contact structure, which improves the current-carrying capacity and contact reliability, and enhances the stability of the product during long-term operation.
- Customizable options: Breaking capacity 5kA~50kA optional; handle color customizable; supports OEM/ODM brand customization services, meeting the personalized needs of different customers.
Key Technical Parameters
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Parameter
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Details
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Standard
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IEC/EN 60947-2
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Pole No
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3P, 4P
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Rated voltage
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AC400V
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Rated current (A)
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16-1600A
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Rated service short-circuit breaking capacity Ics (%Icu)
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5kA~50kA
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Rated ultimate short-circuit breaking capacity Icu (kA)
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8kA~50kA
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Selective category
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Class A
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Overcurrent release type
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Thermomagnetic type
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Wide Application Scenarios of CJMM6RT Series Mould Case Circuit Breaker
With excellent performance and strong adaptability, the CJMM6RT series Mould Case Circuit Breaker is widely used in various industrial and commercial power distribution scenarios, including:
- Industrial workshops: Power distribution protection for production lines, large motors, air compressors and other high-power equipment in manufacturing plants, processing workshops and other places.
- Commercial buildings: Main power distribution cabinets, central air conditioning systems, elevator power supply systems in shopping malls, high-end hotels, office buildings and other large commercial complexes.
- Power distribution rooms: Power distribution and protection in industrial and commercial power distribution rooms, responsible for distributing the main power to each branch circuit and ensuring the safe operation of the entire power distribution system.
- Infrastructure projects: Power distribution systems in transportation hubs (airports, high-speed rail stations), water treatment plants, and sewage treatment plants.
- Motor protection: As a motor protection switch for motors with matching rated current, it protects the motor from overload and short circuit during operation.
Why Choose C&J Electrical’s CJMM6RT Series Mould Case Circuit Breaker?
In the field of Mould Case Circuit Breaker, the CJMM6RT series product from C&J Electrical has obvious competitive advantages:
- Reliable protection performance: Adopts thermomagnetic dual protection mechanism, with adjustable thermal and magnetic parameters, which can accurately respond to overload and short-circuit faults and ensure the safety of the power system.
- Strong adaptability: Wide range of rated current and breaking capacity, suitable for various high-power, complex power distribution scenarios; meets IEC/EN 60947-2 international standards, with stable performance.
- Excellent structural design: Low temperature rise, small volume, multi-contact structure, which ensures the stability and durability of the product during long-term operation.
- Customizable services: Provides a variety of customizable options to meet the personalized needs of different customers and application scenarios.
- Professional technical support: C&J Electrical has a professional technical team that can provide customers with tailored power distribution protection solutions and comprehensive after-sales services.
Get in Touch
If you have any questions about the CJMM6RT series Mould Case Circuit Breaker, such as product specifications, technical details, customization needs, or bulk orders, please feel free to contact C&J Electrical. Our professional team will provide you with high-quality services and reliable power distribution protection solutions to ensure the safe and stable operation of your power system.
Post time: Jan-04-2026