Leading MCB Manufacturer | MOREDAY - 20+ Years Excellence
MOREDAY is a professional MCB manufacturer with over 18 years of experience in designing, producing, and exporting miniature circuit breakers. Located in Yueqing – China’s “Electric Device Metropolis” – we serve distributors, contractors, and electrical engineers across 30+ countries with high-quality, IEC/CE/RoHS certified circuit protection solutions.
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MOREDAY MCB Product Lineup - Complete Technical Specifications
MDB1Z-63H Miniature Circuit Breaker
- Poles: 1P, 2P, 3P, 4P
- Rated Current: 10A-63A
- Breaking Capacity: 10kA, 6kA
- Rated Voltage: 1P:250V, 2P:600V, 3P:750V, 4P:1000V
- Curve Code: B, C
- Mechanical Durability: 10,000 cycles
- Electrical Durability: 2,000 cycles
- Protection Degree: IP40; Wiring port IP20
MDB1Z-63 Miniature Circuit Breaker
- Poles: 1P, 2P, 3P, 4P
- Rated Current: 1A-63A
- Breaking Capacity: 6kA (In ≤ 6A to 40A), 4.5kA (In 50A, 63A)
- Rated Voltage: 1P:250V, 2P:600V, 3P:750V, 4P:1000V
- Curve Code: B, C
- Mechanical Durability: 10,000 cycles
- Electrical Durability: 1,500 cycles
- Protection Degree: IP40; Wiring port IP20
MDB1Z-63S Miniature Circuit Breaker
- Poles: 1P, 2P, 4P
- Rated Current: 10A-63A
- Breaking Capacity: 6kA (In ≤ 6A to 40A), 4.5kA (In 50A, 63A)
- Rated Voltage: 1P:250V, 2P:600V, 3P:750V, 4P:1000V
- Curve Code: B, C
- Mechanical Durability: 10,000 cycles
- Electrical Durability: 1,500 cycles
- Protection Degree: IP40; Wiring port IP20
MDB2Z-63 Miniature Circuit Breaker
- Poles: 2P
- Rated Current: 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A
- Breaking Capacity: 6kA
- Rated Voltage: 800V/1000V~
- Curve Code: B, C
- Mechanical Durability: 15,000 cycles
- Electrical Durability: 1,500 cycles
- Protection Degree: IP40; Wiring port IP20
MDB1Z(NC)-125 Miniature Circuit Breaker
- Poles: 1P, 2P, 3P, 4P
- Rated Current: 80A, 100A, 125A
- Breaking Capacity: 6kA (In ≤ 100A), 4.5kA (In 125A)
- Rated Voltage: 1P:250V, 2P:600V, 3P:750V, 4P:1000V
- Curve Code: B, C
- Mechanical Durability: 10,000 cycles
- Electrical Durability: 1,500 cycles
- Protection Degree: IP40; Wiring port IP20
MDB1-65 Miniature Circuit Breaker
- Poles: 1P, 2P, 3P, 4P
- Rated Current: 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A
- Breaking Capacity: 6kA, 4500A (In 50A, 63A)
- Rated Voltage: 1P: 230/400V, 2P/3P/4P: 400V
- Curve Code: B, C, D
- Mechanical Durability: 10,000 cycles
- Electrical Durability: 6,000 cycles
- Endurance: 20,000 operations
- Protection Degree: IP20
MDB1-125 Miniature Circuit Breaker
- Poles: 1P, 2P, 3P, 4P
- Rated Current: 80A, 100A, 125A
- Breaking Capacity: 6kA
- Rated Voltage: 1P: 230, 2P/3P/4P: 400V
- Curve Code: B, C, D
- Mechanical Durability: 10,000 cycles
- Electrical Durability: 4,000 cycles
- Endurance: 20,000 operations
- Protection Degree: IP20
Why Choose MOREDAY?
MOREDAY is a professional MCB manufacturer with over 18 years of experience in designing, producing, and exporting miniature circuit breakers. Located in Yueqing – China’s “Electric Device Metropolis” – we serve distributors, contractors, and electrical engineers across 30+ countries with high-quality, IEC/CE/RoHS certified circuit protection solutions.
- Industry-Leading Quality: Every MCB undergoes rigorous testing to ensure consistent performance and safety
- Innovative Design: Our R&D team continuously improves our products to meet evolving industry standards
- Comprehensive Support: From selection guidance to after-sales service, we're with you at every step
- Global Compliance: All MOREDAY MCBs meet international safety standards, including IEC, RoHS, CE, and more
- Competitive Pricing: Premium quality without the premium price tag
Precision Engineering - Inside MOREDAY MCB Technology
At MOREDAY, we believe that true quality is revealed in the details. Our MCB manufacturing philosophy centers on “Sublime Micro-Engineering Narratives” – where every component, from the smallest spring to the largest contact assembly, represents surgical precision and artistic interpretation of technical excellence.
- Fire-Retardant Casing: The shell is made of PA66 nylon material, offering V0-grade flame retardancy and high impact resistance.
- Silver Alloy Contacts: We use premium silver-graphite contacts to ensure low contact resistance and prevent welding during short circuits.
- Arc Extinguishing Chamber: An optimized 13-plate grid design rapidly cools and extinguishes arcs, extending the electrical life of the breaker.
- Visual Indicator: Clear Red/Green window indicates contact position for safe maintenance.
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How to Select the Right MCB for Your Application
Proper MCB selection requires considering multiple factors. Use this comprehensive guide to specify the correct circuit breaker for your installation.
Selection Factor | What to Check | MOREDAY Recommendation |
|---|---|---|
Current Rating (In) |
Rated current should exceed normal load current by 15–25% safety margin. |
1–63A for residential & light commercial 63–125A for industrial & distribution panels |
Breaking Capacity (Icn) |
Must exceed maximum prospective short-circuit current at installation point. |
6kA for residential 10kA for commercial 15kA+ for industrial projects |
Trip Curve Type |
Match breaker sensitivity with load type and inrush current characteristics. |
Type B – Lighting & resistive loads Type C – General commercial use (recommended for 80% applications) Type D – Motors, transformers, high inrush equipment |
Number of Poles |
Select according to system phase configuration. |
1P / 2P – Single-phase systems 3P – Three-phase 4P – Three-phase + Neutral (recommended for industrial distribution) |
Voltage Rating |
Rated voltage must be equal or higher than system voltage. |
Up to 400/415V AC standard Higher voltage models available upon request |
Installation Environment |
Consider temperature, dust, humidity, and enclosure protection. |
Operating temperature: -25°C to +60°C IP20 standard, higher IP with enclosure |
Certification & Compliance |
Must comply with international and local standards. |
CE / CB / TÜV certified Compliant with IEC standards |
Special Application (Solar & DC Systems) |
DC systems require specially designed arc-extinguishing structure. |
Use MOREDAY DC MCB for PV combiner boxes and battery storage systems. |
MCB Trip Curve Guide: How to Choose B, C or D for Your Application
Choosing the wrong trip curve may cause nuisance tripping or insufficient short-circuit protection. Understanding load characteristics is critical for system safety and reliability.
Curve Type | Magnetic Trip Range | Best For | Inrush Tolerance | Typical Buyers | MOREDAY Supply |
|---|---|---|---|---|---|
Type B |
3–5 × In |
Lighting circuits, heating elements, residential panels |
Low |
Residential installers, small contractors |
Available in 1P–4P, CE/CB certified |
Type C |
5–10 × In |
Distribution panels, small motors, office buildings |
Medium (industry standard) |
Recommended for 80% of commercial applications |
Default production curve |
Type D |
10–20 × In |
Motors, transformers, compressors, EV charging equipment |
High |
Prevents nuisance tripping in high starting current equipment |
Available upon project request |
Type K |
8–14 × In |
High inrush machinery, X-ray systems, heavy equipment |
MOQ applies for customization | ||
- If your load is mainly lighting → Choose Type B
- If your load includes motors under 3kW → Choose Type C
- If your system includes large motors or compressors → Choose Type D
- If you have any questions, please contact the MOREDAY engineering team.
- What happens if I use Type B for a motor? It may trip instantly during startup due to high inrush current.
- Can Type D replace Type C? Yes, but it may reduce sensitivity and not be suitable for light loads.
MCB Manufacturing Process - From Raw Materials to Certified Products
Our Production Workflow As a vertically integrated MCB manufacturer, we control every stage:
1. Raw Material Inspection
- Imported silver alloy contacts
- High-purity electrolytic copper terminals
- PA66 flame-retardant housing (UL94 V0)
- Bimetallic strips from certified suppliers
2. Automated Assembly
- Robotic contact assembly (±0.01mm precision)
- Arc chamber installation & testing
- Thermal & magnetic element calibration
- Final assembly in Class 10,000 cleanroom
3. 100% Quality Testing
- Automatic electrical testing station
- Temperature rise measurement
- Dielectric strength testing
- Mechanical operation testing (20+ cycles)
4. Certification & Packaging
- Batch traceability labeling
- IEC/CE compliance documentation
- Anti-static packaging
- Custom branding (OEM orders)
Applications
Electrical Solutions for Every Need
As a trusted electrical equipment manufacturer, MOREDAY delivers high-performance electrical solutions designed for residential, commercial, industrial, and renewable energy applications—providing cost savings, operational efficiency, and reliability across diverse industries worldwide.
Solar & Energy Systems
The solar sector relies on specialized DC components for safe high-voltage management and surge protection in photovoltaic systems.
Industrial Manufacturing
Industrial manufacturing requires robust electrical controls for heavy machinery and automation systems.
Commercial & Residential
Buildings need electrical solutions prioritizing safety and efficiency while meeting codes.
Marine & Offshore Industries
Marine applications require components withstanding saltwater, humidity, and vibration.
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Discover Our Best-Selling Electrical Equipment – High Efficiency, Reliable Performance, and Trusted by Electrical Equipment Suppliers Worldwide.
More Than Just a MCB Manufacturer
At MOREDAY, we go beyond manufacturing MCB by offering a suite of value-added services tailored to meet your project needs. Our commitment to excellence ensures that every customer receives personalized attention, expert guidance, and seamless support throughout their journey with us.
Technical Consultation
Our engineering team provides professional DC protection design support for solar PV systems. From breaker selection to full combiner box configuration, we help you ensure safety, compliance, and long-term reliability.
OEM & Custom Solutions
We support logo printing, customized voltage ratings, special tripping curves, and private label packaging. MOREDAY helps distributors and project contractors build competitive branded products for local markets.
Certified Quality Assurance
Our MCB products comply with CE, CB, and TÜV standards. Each unit undergoes strict testing for breaking capacity, temperature rise, and durability to meet international project requirements.
Global Project Experience
MOREDAY products are widely used in solar power plants, energy storage systems, EV charging stations, and industrial applications across Europe, Asia, and Africa.
Knowledge About MCB
- What is an MCB?
A miniature circuit breaker (MCB) is an automatically operated electrical switch designed to protect circuits from overcurrent damage caused by overloads or short circuits. Unlike fuses that must be replaced after operating, MCBs can be reset and reused indefinitely. They work through two protection mechanisms: a thermal element (bimetallic strip) that provides time-delayed protection against overloads, and a magnetic element (solenoid) that provides instantaneous protection against short circuits, typically operating in 0.01-0.1 seconds.
- How Does an MCB Work?
Modern MCBs from our manufacturing facility employ two protection mechanisms:
1. Thermal Protection (Overload)
- Bimetallic strip heats and bends under prolonged overcurrent
- Provides time-delayed tripping for overload conditions
- Allows temporary harmless overcurrents (motor starting)
- Typically trips at 1.13-1.45x rated current within 1 hour
2. Magnetic Protection (Short Circuit)
- Electromagnetic solenoid activates under sudden high current
- Provides instantaneous tripping for fault conditions
- Operates in milliseconds (0.01-0.1 seconds)
- Prevents arc flash and equipment damage
- Key Components of an MCB
- Operating Mechanism: The handle and latching mechanism
- Contacts: The conducting parts that connect and disconnect the circuit
- Arc Extinguishing Chamber: Quenches the arc formed during contact separation
- Thermal Element: Bimetallic strip for overload protection
- Magnetic Element: Solenoid for short-circuit protection
- Terminals: Connection points for incoming and outgoing cables
- What is the difference between B, C, and D trip curves?
B-curve MCBs trip at 3-5 times the rated current and are ideal for resistive loads like lighting and heating. C-curve MCBs trip at 5-10 times the rated current, making them suitable for general-purpose applications including slightly inductive loads like small motors—this is the most commonly used curve representing about 90% of installations. D-curve MCBs trip at 10-20 times the rated current and are designed for highly inductive loads with high inrush currents such as large motors, transformers, and welding equipment.
- How do I determine the correct MCB size for my application?
Calculate the maximum current draw of your circuit, then select an MCB with a rating slightly higher than this value. Consider factors like cable size, load type, and potential future expansion. For specific guidance, consult our selection guide or contact our technical team.
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We provide samples for free, you just need to tell us what you need