As a core component in low-voltage electrical distribution systems, Mcb Miniature Circuit Breaker (MCB) plays a vital role in protecting circuits and electrical equipment from faults. Different from traditional fuses, MCB is reusable, easy to operate and has precise protection performance, making it widely used in residential, commercial and industrial scenarios. Zhejiang C&J Electrical co., ltd. (referred to as C&J Electrical) has rich experience in MCB R&D and production, and its CJM8-63-II Mcb Miniature Circuit Breaker stands out with excellent performance and humanized design, providing reliable protection for various electrical systems.
Core Working Principle of Mcb Miniature Circuit Breaker
MCB works on the principle of thermal – magnetic tripping mechanism, which combines both thermal and magnetic elements to detect the electrical faults in the circuit. Thermal element is a bimetallic strip that is used for protection against overload conditions. This dual-element design enables MCB to respond to different types of circuit faults accurately and efficiently, achieving targeted protection effects.
For overload protection, the thermal element (bimetallic strip) is the core. When the circuit current exceeds the rated value for a long time (overload), the bimetallic strip is heated and deformed by the current. After a certain delay (adjusted according to the overload degree), the deformed bimetallic strip triggers the tripping mechanism, cutting off the circuit. This delayed action avoids unnecessary tripping caused by short-term current fluctuations, while ensuring that the circuit is disconnected in time to prevent wire overheating and equipment damage.
For short-circuit protection, the magnetic element (electromagnet) takes effect. When a short-circuit fault occurs, the circuit current surges instantaneously. The electromagnet generates a strong magnetic field under the action of large current, which instantly attracts the armature and drives the tripping mechanism to act. This instantaneous tripping can cut off the fault circuit in milliseconds, preventing the spread of short-circuit hazards and avoiding serious damage to electrical equipment and distribution systems.
Overview & Core Functions of Mcb Miniature Circuit Breaker
Product Overview
Mcb Miniature Circuit Breaker is a small-sized, reusable protective electrical device designed for low-voltage distribution systems (usually below 1000V AC). It integrates overload protection, short-circuit protection and isolation functions, and is widely used in the final stage of power distribution. Compared with fuses, MCB has the advantages of no need to replace after tripping, intuitive fault indication, and convenient reset, which greatly improves the maintenance efficiency of the electrical system.
MCB is classified into different curve types (B, C, D) according to the tripping characteristic, which are suitable for different load types. It adopts a modular design with a compact structure, which can be installed on a 35mm DIN rail, saving installation space and facilitating centralized management of distribution boxes. With the continuous improvement of electrical safety standards, high-performance MCB has become a standard configuration in modern buildings and industrial sites.
Core Functions
- Overload protection: Through the thermal tripping mechanism, it cuts off the circuit after a delay when the current is overloaded for a long time, preventing wire overheating and insulation aging.
- Short-circuit protection: Through the magnetic tripping mechanism, it trips instantly when a short-circuit fault occurs, isolating the fault point and avoiding equipment damage and fire hazards.
- Isolation function: After tripping, it can reliably isolate the fault circuit from the power supply, ensuring the safety of maintenance personnel during inspection and maintenance.
- Contact position indication: Intuitively displays the on-off status of the circuit, facilitating users to quickly judge the operation status and fault location.
- Reusable performance: After troubleshooting, it can be reset manually without replacing components, reducing maintenance costs and downtime.
Application Scenarios of Mcb Miniature Circuit Breaker
With its compact structure, reliable performance and wide adaptability, Mcb Miniature Circuit Breaker is widely used in various low-voltage electrical scenarios:
- Residential buildings: Used as the main switch and branch switch in household distribution boxes, protecting circuits such as lighting, sockets, air conditioners and household appliances, ensuring the safety of household electricity use.
- Commercial buildings: Shopping malls, office buildings, hotels and other places, used for protection of branch circuits such as lighting systems, air conditioning systems, and office equipment, ensuring the stable operation of public electrical facilities.
- Industrial workshops: Small and medium-sized factories and workshops, used for protection of auxiliary circuits, lighting circuits and small power equipment, adapting to the complex working environment of industrial sites.
- Public places: Schools, hospitals, libraries and other places, providing reliable circuit protection for public electrical equipment, ensuring the safety of personnel and property.
- Other scenarios: Villas, apartments, temporary construction sites and other places that require small-sized, easy-to-install circuit protection devices.
C&J Electrical’s CJM8-63-II MCB: Core Advantages & Product Overview
C&J Electrical’s CJM8-63-II Mcb Miniature Circuit Breaker is a high-performance product designed for modern low-voltage distribution systems. It integrates excellent protection performance and humanized design, and its core construction features and technical parameters fully meet the needs of various application scenarios. The details are as follows:
Construction & Core Advantages
- Strong short-circuit resistance: High short-circuit capacity of 6KA, which can reliably withstand short-circuit current impact, ensuring the safety of the device and the circuit.
- Wide current adaptation: Designed to protect circuits carrying large current up to 63A, covering multiple rated current specifications to meet different load requirements.
- Intuitive status indication: Equipped with contact position indication, users can quickly judge the on-off status of the circuit, facilitating daily inspection and fault troubleshooting.
- Versatile application: Suitable for use as the main switch in household and similar installations, with a compact modular design that saves installation space and is easy to install on DIN rails.
- High safety performance: Complies with international standards, adopts high-quality materials and precise tripping mechanism, ensuring stable and reliable protection performance.
- Customizable service: Supports OEM brand customization services, which can be tailored according to customer needs to meet the personalized requirements of different market segments.
Main Technical Parameters
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Parameter
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Details
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|---|---|
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Standard
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IEC/EN 60898-1
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Rated Current
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6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A
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Rated Voltage
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230/400VAC (240/415VAC)
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Rated Frequency
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50/60Hz
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Number of Pole
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1P, 1P+N, 2P, 3P, 3P+N, 4P
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Module size
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17.5mm
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Curve type
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B, C, D Type
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Breaking capacity
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6000A
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Optimum operating temperature
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-5℃ to 40℃
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Terminal Tightening torque
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5N-m
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Terminal Capacity (top)
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25mm²
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Terminal Capacity (bottom)
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25mm²
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Electro-mechanical endurance
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4000 cycles
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Mounting
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35mm Din Rail
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Suitable Busbar
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PIN Busbar
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Why Choose C&J Electrical’s CJM8-63-II MCB?
In the field of Mcb Miniature Circuit Breaker, the CJM8-63-II MCB from C&J Electrical has obvious competitive advantages, becoming the preferred choice for customers pursuing high quality and stable performance:
- Reliable protection performance: Complies with IEC/EN 60898-1 international standard, with precise thermal-magnetic tripping mechanism and 6KA short-circuit breaking capacity, ensuring comprehensive fault protection.
- Wide adaptability: Multiple pole numbers, curve types and rated current specifications optional, suitable for residential, commercial and industrial applications.
- Humanized design: Compact modular structure, 17.5mm module size, easy to install and maintain; contact position indication improves operation convenience.
- Durable quality: High-quality materials and 4000 cycles of electro-mechanical endurance, ensuring long-term stable operation in harsh environments.
- Professional customization & support: Provides OEM brand customization services; C&J Electrical’s professional technical team provides tailored solutions and comprehensive after-sales services.
Get in Touch
If you have any questions about the CJM8-63-II Mcb Miniature 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 electrical protection services and reliable solutions to ensure the safe and stable operation of your electrical system.
Post time: Jan-22-2026