Molded Case Circuit Breaker

Your Professional Molded Case Circuit Breaker Supplier！

Founded in 2010, Zhejiang Westroom Electric Co., Ltd. has a registered capital of 10 million RMB and is a professional enterprise integrating the design, manufacturing, sales, and service of plastic-cased circuit breakers, residual current circuit breakers, miniature circuit breakers, and other related products.The company primarily produces plastic-cased circuit breakers, residual current circuit breakers, miniature circuit breakers, and other related products.

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Why Choose Us

Stable Quality

Equipped with advanced production and testing facilities, Westroom Electric implements strict quality control throughout the manufacturing process. This helps ensure reliable product performance, consistent quality, and stable supply for long-term projects.

Our Service

Westroom Electric is focuses on providing responsive pre-sales, in-sales, and after-sales support to ensure customer satisfaction throughout the cooperation process.

Sales Market

The company supplies products to power transmission and distribution engineering companies, agents, and project contractors in Europe, the United States, Japan, the Middle East, Russia, and Southeast Asia, as well as the domestic market.

Overview: Molded Case Circuit Breaker

A Molded Case Circuit Breaker (MCCB) is an electrical protection device designed to safeguard circuits from overloads, short circuits, and ground faults. Named for its durable, insulated molded housing.

Product Specification

Parameter	Value
Rated Voltage	DC 1000V / 1500V
Rated Current (In)	63A, 80A, 100A, 125A, 160A, 250A, 400A, 630A, 800A, 1000A, 1250A
Number of Poles	2P, 3P, 4P
Rated Ultimate Short-Circuit Breaking Capacity (Icu)	DC 20kA / 30kA / 50kA
Operating Temperature	-40°C to +85°C
Protection Function	DC Overload, DC Short Circuit, DC Arc Fault
Mechanical Life	20,000 operations
Electrical Life	6,000 operations
Terminal Type	Cable / Busbar
Mounting Type	Fixed
Standards Compliance	IEC 60947-2 (with Annex L for DC PV applications)

Product features

Adjustable Trip Settings: Allows fine-tuning of trip thresholds for different load requirements, offering flexibility in protection.

High Current Rating: Handles a wide range of currents, typically from 16A to over 1,600A, making it suitable for low- and high-power circuits.

Durable Molded Case: Ensures internal components are protected from dust, moisture, and mechanical impacts, enhancing breaker longevity.

Thermal-Magnetic Trip Mechanism: Combines thermal protection for overloads and magnetic protection for short circuits to improve safety.

Broad Voltage Range Compatibility: Operates across various voltage levels, up to 1,000V, making it versatile for different systems.

Longevity and Reliability: Withstands multiple trips without performance issues, ensuring reliable long-term use.

Compliance with Safety Standards: Meets international standards such as IEC 60947-2 or UL 489, ensuring performance and regulatory compliance.

Components

Frame

Protects internal parts of the circuit breaker

Operating mechanism

Opens and closes the circuit breaker, typically a handle or lever to manually operate the circuit breaker

Trip unit

Detects and interrupts an overload or short circuit

Contacts

Allows current flow when closed and prevents current flow when open

Arc extinguisher

Extinguishes the arc formed when the contacts open thus preventing damage to the device and surrounding equipment

Common types

B MCCBs

Type B MCCBs are designed to trip whenever the current flowing through them exceeds 3 to 5 times their rated current. The tripping time for this circuit breaker ranges from 0.04 to 13 seconds.

C MCCBs

These MCCBs provide more protection compared to Type B MCCBs. They trip at 5 to 10 times the rated current with a delay time of 0.04 to 5 seconds. Type C MCCBs offer a balance between short-circuit and overload protection.

DC Molded Case Circuit Breaker suppliers

D MCCBs

Type D MCCBs are designed for high-inrush current applications such as large industrial machinery. These breakers trip at 10 to 20 times the rated current, and their response time ranges from 0.04 to 3 seconds.

K MCCBs

Type K MCCBs are mainly effective in protecting circuits that use two-core cables. They trip at 8 to 12 times the rated current and are commonly used in installations with sensitive equipment.

Application

Protecting Generators: They usually produce hundreds of amps in output and require expensive generators. MCCBs, which can handle the current ratings, provide the protection needed.

Protecting Electric Feeders: If you are using feeder circuits to distribute electric current, they can carry hundreds of amps. In some instances, you may also have additional circuits that need trip settings. MCCBs come in handy in both situations.

Welding Machines: Some welding applications can draw very high currents, necessitating the use of MCCBs, as miniature circuit breakers are not capable of handling such high currents.

Protecting Capacitor Banks: These are used to correct power factors in industrial and commercial electrical systems. If the currents they draw are very high, MCCB protection becomes a necessity to reduce the currents.

Protecting Motors: Electric motors also need to be adequately protected, and MCCBs do this work very well. Inrush current may need to be adjusted, providing the necessary overload protection without tripping.

Other Services

Advanced Arc-Extinguishing Technology

Features an optimized arc chute design that rapidly interrupts fault currents in milliseconds, minimizing thermal and mechanical stress on downstream equipment.

Versatile Trip Unit Options

Available with high-precision electronic or reliable thermal-magnetic trip units. Adjustable current settings allow for precise matching to specific load profiles.

High Breaking Capacity, Compact Footprint

Delivers exceptional short-circuit breaking capacity (Icu/Ics) within a compact frame. This space-saving design optimizes panel layout and reduces overall enclosure costs.

Field-Installable Modular Accessories

Easily accommodates snap-on accessories—including shunt trips, undervoltage releases (UVR), auxiliary contacts, and alarm switches—to support complex control logic and remote monitoring.

Certifications

Package & Delivery

Package: Standard export package or Custom
Delivery: By air express, by sea

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FAQ

Q: Where are molded case circuit breakers used?

A: MCBs are used in large commercial and industrial settings for high-current circuits, so they protect short circuits, equipment failures, overloads, etc.

Q: Does a molded case switch trip?

A: Yes, an MCCB does trip to defend against short circuits & overloads.

Q: How does a molded case breaker protect against sustained overloads and short circuits?

A: MCCBs defend from short circuits and sustained overloads with a blend of magnetic trip and thermal mechanisms. Magnetic protection reacts to immediate high currents and thermal protection notices prolonged over currents.

Q: What two elements make up a molded-case circuit breaker?

A: A thermal element is used for overload protection, whereas a magnetic element is used for short-circuit protection.

Q: Are you manufacturer or trading company?

A: We are manufacturer.

Q: What's your best delivery time?

A: Within 15-30 days.

Q: What is the quality control of your product?

A: Follow strictly quality control measures for implementation,

Q: Will your company provide free sample?

A: It depends on which sort of item you want to get. Some can be provided free of charge, however, the client shall assume the shipping fees himself.

Q: Is OEM open to clients?

A: Yes, we can provide both OEM and ODM service.

Q: What is the payment of sample?

A: T/T and Alipay both acceptable.

Q: What is your packing?

A: Yes, our packaging is genuine original packaging. Of course, we can also provide neutral packaging or according to your requirements

Q: What is your sample policy?

A: If we have stock, we can provide samples, but the customer must pay the sample fee and express fee Question

Q: Have you tested all your goods before shipment?

A: Yes, we will conduct 100% test before delivery, and we will send detailed photos of parts for your approval .

Q: How can you maintain a long-term good relationship with our business?

A: We maintain good quality and competitive prices to ensure the interests of our customers.

As one of the leading molded case circuit breaker manufacturers and suppliers in China, we have world-leading production equipment and strong manufacturing capabilities. Please feel free to wholesale advanced molded case circuit breaker at competitive price from our factory.

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