China Professional Miniature Circuit Breaker Factory
We invite you to order high-quality Miniature Circuit Breakers from CDADA. As a professional manufacturer with decades of experience, we offer a comprehensive range of configurations and support OEM customization services to ensure compliance with various domestic Chinese and international certifications and standards. Please feel free to contact us for a quotation.
What Is a Miniature Circuit Breaker?
A Miniature Circuit Breaker (MCB) is a compact, resettable low-voltage protection device designed to safeguard electrical circuits from overloads and short circuits. Operating at rated voltages up to 240/415V AC (50/60Hz) with current ratings from 0.5A to 125A, MCBs serve as the primary circuit protection device in residential, commercial, and light industrial electrical distribution systems.
The MCB represents a fundamental advancement over traditional fuses, offering automatic tripping upon fault detection and manual reset capability once the fault is cleared—eliminating component replacement and reducing maintenance costs. Each MCB features a specific current rating matched to the protected circuit, ensuring precise protection coordination.
MCB Product Categories & Configurations
|
Classification |
Type |
Current Range |
Key Characteristics |
|
Tripping Characteristic (Curve) |
Type B |
0.5A – 63A |
3-5×In instantaneous trip, low inrush loads (lighting, resistive heating) |
|
Type C |
0.5A – 125A |
5-10×In trip, moderate inrush (motors, air conditioners, small appliances) |
|
|
Type D |
0.5A – 63A |
10-20×In trip, high inrush (transformers, large motors, welding equipment) |
|
|
Type K |
0.5A – 63A |
8-12×In trip, commercial/industrial motor loads |
|
|
Type Z |
0.5A – 40A |
2-3×In trip, sensitive electronic equipment, semiconductor protection |
|
|
Pole Configuration |
Single-Pole (SP) |
0.5A – 63A |
Phase protection in single-phase circuits |
|
Double-Pole (DP) |
0.5A – 63A |
Phase + neutral protection, common trip bar |
|
|
Triple-Pole (TP) |
0.5A – 125A |
Three-phase protection, industrial distribution |
|
|
Four-Pole (4P) |
0.5A – 125A |
Three-phase + neutral, common trip mechanism |
|
|
Breaking Capacity |
Standard (S) |
3kA – 6kA |
Domestic installations, low fault level networks |
|
Enhanced (H) |
10kA |
Commercial buildings, medium fault levels |
|
|
High (G) |
15kA – 25kA |
Industrial mains, high fault capacity |
|
|
Mounting Standard |
DIN Rail (IEC 60715) |
All ratings |
35mm top-hat rail (TH35), quick snap-on installation |
|
Panel Mount |
0.5A – 63A |
Screw-fixed base, legacy installations |
Current Rating Series (Preferred Values): 0.5A,1A,2A, 4A, 6A, 10A, 16A, 20A, 25A, 32A, 40A, 50A, 63A, 80A, 100A, 125A
Core Functions & Protection Capabilities
Dual-Element Protection Mechanism
|
Function |
Actuation Principle |
Technical Parameters |
|
Overload Protection (Thermal) |
Bimetallic strip heat expansion |
1.05×In: No trip (2h), 1.3×In: Trip ≤1h (In≤32A), ≤2h (In>32A), 1.45×In: Trip <1h |
|
Short-Circuit Protection (Magnetic) |
Solenoid plunger instantaneous |
Type B: 3-5×In, Type C: 5-10×In, Type D: 10-20×In, <20ms operation |
|
Isolation Function |
Positive contact separation |
Suitability for isolation per IEC 60898-1, contact gap verification |
|
Trip Indication |
Mechanical flag/window |
Distinct ON/OFF position, trip-free mechanism prevents closure on fault |
Advanced Design Features
Modern MCBs incorporate sophisticated engineering elements:
Quick-make, quick-break mechanisms: Independent of handle operation speed, ensuring consistent contact closure
Trip-free design: Prevents manual closure during sustained fault conditions
Line-load reversibility: Input/output terminals interchangeable for installation flexibility
Application Environments & Use Cases
|
Installation Environment |
Specific Application |
Typical Specifications |
|
Residential Buildings |
Lighting circuits, socket outlets, HVAC, water heaters |
6A-32A Type B/C, 6kA Icn, DIN rail mounting |
|
Commercial Offices |
Distribution boards, computer equipment, UPS circuits |
10A-63A Type C, 10kA Icn, 4-pole for 3-phase |
|
Retail & Hospitality |
Shop lighting, refrigeration, kitchen equipment |
16A-40A Type C, 10kA, common trip for multi-pole |
|
Industrial Control Panels |
Machine tools, motor control circuits, automation |
10A-63A Type D, 15kA, high mechanical endurance |
|
Infrastructure |
Metro stations, airports, hospitals, data centers |
32A-125A Type C, 25kA, current limiting Class 3 |
|
Renewable Energy |
Solar string protection, battery systems, inverters |
10A-63A DC-rated (IEC 60898-2), 250V/500V/1000V DC |
|
Marine & Offshore |
Ship distribution, offshore platforms |
Tropicalized (T2), corrosion-resistant, 55°C ambient |
Manufacturing Process & Production Workflow
High-Volume Precision Manufacturing Sequence
Raw Material IQC → Thermoplastic Injection Molding → Contact System Stamping → Bimetallic Element Assembly → Magnetic Coil Winding → Arc Chute Integration → Mechanism Assembly → Calibration & Testing → Final QC → Packaging
Critical Manufacturing Stages
|
Stage |
Process Details |
Quality Control Points |
|
Housing Injection Molding |
High-impact thermoplastic (PA66, PBT) with 30% glass fiber, 280-320°C melt temperature, 800-1200 bar injection pressure |
Dimensional tolerance ±0.05mm, impact strength >7 kJ/m², tracking index >600V, UL 94 V-0 flammability |
|
Contact Stamping & Plating |
Silver-nickel (AgNi 90/10) or silver-cadmium oxide contacts, progressive die stamping, barrel plating 8-12μm silver |
Hardness HV 80-120, contact resistance <100μΩ, plating thickness XRF verification |
|
Bimetallic Element Production |
Inconel/passivated steel composite, precision rolling, heat treatment for deflection characteristics |
Deflection rate 0.15-0.25mm/°C, calibration at 20°C reference, ±3% batch consistency |
|
Magnetic Coil Manufacturing |
Copper wire (0.3-0.8mm diameter), automated winding, vacuum varnish impregnation |
Turns count ±1%, DC resistance ±5%, insulation resistance >100MΩ |
|
Arc Chute Assembly |
Steel splitter plates (0.5mm), ceramic arc grids, optimized deionizing chamber geometry |
Magnetic flux verification, dielectric strength 2.5kV, dimensional ±0.02mm |
|
Mechanism Integration |
Spring steel charging system, toggle mechanism, trip-free override, energy storage springs |
Mechanical endurance 20,000 cycles, trip force 3-8N, toggle reliability |
|
Final Calibration |
Automated time-current testing at 1.05×In, 1.25×In, 5×In (or curve-specific) |
Trip time ±20% tolerance, instantaneous trip verification, marking permanence |
Primary Raw Materials & Component Specifications
|
Component |
Material Specification |
Supplier Standards |
Key Properties |
|
Moulded Housing |
PA66 GF30 (polyamide 66, 30% glass fiber) or PBT GF30 |
IEC 60664-1, UL 94 V-1 |
Tracking index >600V, heat resistance 160°C, impact strength >7 kJ/m², halogen-free available |
|
Operating Handle |
PC/ABS blend or PA66 |
ISO 527 |
Tensile strength >50MPa, UV stabilized, colorfast |
|
Fixed/Moving Contacts |
Electrolytic copper (Cu-ETP C11000) + AgNi 90/10 or AgCdO plating |
ASTM B152 |
Conductivity ≥100% IACS, arc erosion resistance, anti-welding |
|
Bimetallic Strip |
Inconel 718/passivated steel composite (ASTM TM2) or brass/steel |
ASTM B388 |
Deflection rate 0.2mm/°C, stability ±3% over 20 years, creep resistance |
|
Magnetic Coil |
Enameled copper wire (Class F 155°C or Class H 180°C) |
IEC 60317 |
Breakdown voltage >3kV, solderability 390°C/2s, flexibility |
|
Arc Splitter Plates |
Cold-rolled steel SPCC-SD (0.5mm) with ceramic coating |
JIS G 3141 |
Magnetic permeability >2000, heat resistance >1000°C, arc quenching |
|
Operating Springs |
Oil-tempered carbon steel SWP-B or stainless steel 301 |
JIS G 3522 |
Fatigue life >50,000 cycles, tensile strength 1800-2200MPa |
|
Terminals |
Brass C36000 or copper C11000 with tin plating (5-8μm) |
ASTM B16 |
Current density 1.0-1.2 A/mm², torque withstand 1.5-2.5Nm, corrosion resistance |
|
Mounting Clip |
Spring steel 65Mn or stainless steel 304 |
GB/T 1222 |
Clamp force 50-100N, DIN rail compatibility (EN 60715) |
Standards Compliance & Testing Protocols
International Standards Framework
|
Standard |
Scope |
Applicable Ratings |
|
IEC 60898-1 |
Circuit breakers for AC operation (household & similar) |
Global baseline for AC MCBs up to 125A, 415V |
|
IEC 60898-2 |
Circuit breakers for AC and DC operation |
DC-rated MCBs for solar, battery, rail applications |
|
EN 60898-1 |
European harmonized version |
CE marking, EU market compliance |
|
IEC 60947-2 |
Low-voltage switchgear - Circuit-breakers |
Industrial MCBs >80A, higher breaking capacities |
|
GB/T 10963.1 |
Chinese national standard equivalent |
CCC certification, China market |
Mandatory Type Tests (IEC 60898-1)
|
Test Category |
Specific Test |
Acceptance Criteria |
|
Marking & Documentation |
Indelibility of marking |
Permanent after solvent wiping, temperature cycling |
|
Mechanical Integrity |
Reliability of screws, connections, terminals |
No loosening after vibration, torque withstand |
|
Safety |
Protection against electric shock |
IP20 minimum, finger-proof terminals |
|
Dielectric Properties |
Power-frequency withstand (2kV/1min), impulse (6kV) |
No breakdown, no flashover |
|
Temperature Rise |
Continuous current at 40°C ambient |
Terminals ≤60K, case ≤40K |
|
28-Day Test |
Sustained 1.13×In loading |
No trip, no degradation |
|
Tripping Characteristics |
Conventional time-current verification |
1.05×In: no trip (2h), 1.3×In/1.45×In: trip within limits |
|
Mechanical Endurance |
20,000 no-load operations |
<5% parameter drift, no failure |
|
Electrical Endurance |
4,000 load operations at rated current |
Contact wear <50%, trip characteristics maintained |
|
Short-Circuit Breaking |
Icn (rated), Ics (service) verification |
3 operations, successful interruption, dielectric recovery |
|
Environmental |
Mechanical shock, impact, heat, fire, rusting |
Functional after conditioning, no safety degradation |
Factory Quality Control & Inspection Standards
Incoming Material QC (IQC)
|
Material |
Inspection Items |
Sampling Plan |
Equipment |
|
Thermoplastic granules |
Glass content, viscosity, moisture, color |
Per batch, COA verification |
Melt flow indexer, moisture analyzer, spectrophotometer |
|
Copper wire (contacts) |
Purity ≥99.9%, conductivity, annealing |
AQL 0.65 |
Spectrometer, conductivity meter |
|
Silver plating solution |
Metal concentration, pH, impurities |
Daily monitoring |
Atomic absorption spectrometer |
|
Bimetallic strip |
Deflection rate, resistance, stability |
Per batch, sample testing |
Thermal oven, deflection measurement |
|
Enameled wire |
Diameter, insulation thickness, breakdown voltage |
AQL 1.0 |
Micrometer, dielectric tester |
|
Spring steel |
Tensile strength, fatigue resistance, forming |
Per batch |
Tensile machine, fatigue tester |
In-Process Quality Control (IPQC)
|
Station |
Control Parameters |
Frequency |
Method |
|
Injection molding |
Temperature 280-320°C, pressure 800-1200 bar, cycle time |
Every cycle |
SCADA monitoring, SPC charts |
|
Contact stamping |
Dimension ±0.02mm, burr <0.01mm, plating thickness |
Every 30 minutes |
Optical comparator, XRF analyzer |
|
Bimetal calibration |
Deflection at reference temperature, creep test |
Every 100 units |
Automated calibration station |
|
Coil winding |
Turns count, tension control, layer uniformity |
Every unit |
Automated winding machine with feedback |
|
Mechanism assembly |
Toggle force, trip-free function, contact gap |
Every unit |
Force gauge, automated test bench |
|
Final assembly |
Torque marking, contact alignment, handle operation |
Every unit |
Vision system, functional tester |
Final Quality Control (FQC) & Outgoing QC (OQC)
|
Test Item |
Standard |
Sample Size |
|
Dielectric withstand voltage |
2kV AC/1min |
100% |
|
Insulation resistance |
>100MΩ @ 500V DC |
100% |
|
Contact resistance |
<100μΩ per pole |
100% |
|
Tripping characteristics |
1.05×In (no trip), 1.3×In (trip), 5×In (instantaneous) |
100% |
|
Mechanical operation |
5 ON-OFF cycles, trip-free verification |
100% |
|
Clearance between open contacts |
≥3mm (per IEC 60898-1) |
100% |
|
Visual & dimensional inspection |
Zero defects on critical dimensions |
100% |
|
Marking permanence |
Solvent wiping, abrasion test |
AQL 1.0 |
|
Packaging integrity |
Drop test, vibration (ISTA 3A), labeling |
Per lot |
Production Infrastructure & Manufacturing Capability
Advanced Production Equipment
|
Equipment Category |
Machine Specification |
Function |
Capacity |
|
Injection Molding |
120-ton thermoplastic injection press (Arburg/Engel) with robotic handling |
MCB housing, cover, arc chamber production |
5,000 housings/day |
|
Progressive Stamping |
60-ton high-speed press (Bruderer/Yamada Dobby) with die protection |
Contact stamping, terminal forming |
30,000 contacts/day |
|
Surface Treatment |
Automated barrel plating line (silver, tin) |
Contact plating thickness 8-12μm |
5,000 kg/day |
|
Assembly |
High-speed assembly |
Mechanism assembly, calibration, testing |
3,000 units/day per line |
|
Testing Equipment |
Automated primary injection test set (3-125A, 10,000A fault capacity) |
Time-current curve verification |
500 units/hour |
|
Mechanical endurance tester (20,000 cycles, IEC 60898-1 Clause 9.11) |
Life testing, wear monitoring |
200 units simultaneous |
|
|
EMC test chamber (for electronic accessories) |
Immunity/emission testing |
100 units/day |
Production Capacity & Lead Times
|
Product Category |
Monthly Capacity |
Standard Lead Time |
Urgent Order Capability |
|
Standard MCB (0.5A-63A, SP/DP) |
1,000,000 units |
3-4 weeks |
3 days (stock components) |
|
Industrial MCB (80A-125A, TP/4P) |
200,000 units |
3-4 weeks |
5 days |
|
DC MCB (IEC 60898-2) |
100,000 units |
3-4 weeks |
5 days |
|
Custom configurations (special curves, accessories) |
Project basis |
4-6 weeks |
2 weeks |
Engineering & Technical Team Structure
|
Department |
Personnel |
Expertise |
Responsibilities |
|
R&D Engineering |
5 engineers |
Low-voltage protection, material science, electromagnetic design, automation |
New product development (B/C/D/K/Z curves), customization, patent portfolio (30+ patents) |
|
Process Engineering |
18 engineers |
Injection molding, precision stamping, plating, lean manufacturing |
Production line optimization, SOP documentation, yield improvement (>99%), automation integration |
|
Testing & Validation |
12 engineers |
High-volume testing, environmental simulation, reliability engineering |
Type testing coordination, routine test automation, failure analysis, certification management |
|
Quality Assurance |
30 technicians |
ISO 9001, IATF 16949, statistical process control (SPC), metrology |
Supplier audit, process audit, corrective action management, calibration laboratory |
|
Application Engineering |
8 engineers |
Residential/commercial electrical design, selective coordination, field support |
Customer technical support, distribution board design, training programs |
Certifications & Compliance Documentation
|
Certification |
Issuing Body |
Scope |
Validity |
|
ISO 9001:2015 |
TÜV SÜD / SGS / Bureau Veritas |
Quality management system |
Annual surveillance |
|
IEC 60898-1 Type Test |
Intertek |
Product safety & performance |
Per product series |
|
CE Marking |
Notified Body |
EU market access |
Design-dependent |
|
CCC (China) |
CQC |
Chinese compulsory certification |
5-year validity |
|
CB Scheme |
IECEE |
International certification |
Per product series |
|
SEMKO (Sweden) |
Intertek |
Nordic market safety approval |
Per product series |
Why Our MCB Manufacturing Stands Apart
Our production facility represents 40 years of specialization in miniature circuit breaker manufacturing, delivering products that exceed global standards through:
High-volume precision manufacturing: Automated lines producing 1,000,000+ units monthly with <50ppm defect rates
Vertical integration: In-house housing injection molding, contact stamping/plating, and DIN rail production ensuring complete supply chain control
Advanced testing infrastructure: $2M+ invested in automated primary injection testing, mechanical endurance verification (20,000 cycles), and EMC compliance
Global certification strategy: Multi-standard compliance (IEC 60898-1, EN, GB, ) enabling seamless market entry across 120+ countries
Customization capability: From specialized tropical formulations (T2, 55°C ambient) to DC-rated versions (250V/500V/1000V) and unique curve characteristics
For technical specifications, distribution board design support, selective coordination studies, or factory audit scheduling, our engineering team provides direct consultation to ensure your residential, commercial, or industrial electrical installations meet both protection requirements and long-term reliability objectives.
- View as
Miniature Circuit Breaker REAL 6KA
Contact CDADA today and let us be your supplier of Miniature Circuit Breaker REAL 6KA, a high-quality miniature circuit breaker compliant with IEC/EN60898 for reliable circuit protection. It features thermal magnetic tripping and a flame-retardant shell, is easy to install on DIN rail, and is simple to maintain. It combines stable performance with durable design, achieving long service life for residential and industrial power distribution.
Miniature Circuit Breaker DPN 6KA
CDADA Miniature Circuit Breaker DPN 6KA is perfect for bulk procurement, a high-quality 1P+N miniature circuit breaker compliant with IEC60898-1 for safe household and commercial circuit protection. It uses dual break-point design and stable thermal-magnetic tripping, easy to install on DIN rail and simple to maintain. It combines reliable structure with long service life, ensuring safe power supply for various low-voltage power systems.
3 Phase MCB Breaker
Choose CDADA as your manufacturer and supplier, and get our 3 Phase MCB Breaker, CE CB CCC certified with 6kA breaking capacity for industrial and commercial power distribution. This product uses flame-retardant shell and precise thermal-magnetic tripping, is easy to mount on DIN rail and simple to maintain. It combines stable performance with long mechanical and electrical life, ensuring safe circuit protection for three-phase power systems.
125 15KA Miniature Circuit Breaker
As a reliable manufacturer of 125 15KA Miniature Circuit Breaker, CDADA's product is a high-performance 125A MCB with 15kA breaking capacity for heavy-duty power distribution. It uses PA66 flame-retardant shell and dual arc chamber design, easy to mount on DIN rail and simple to maintain. It combines silvered contact structure with industrial-grade durability, achieving ultra-long service life for large-current circuits.
6KA 10kA Miniature Circuit Breaker
CDADA 6kA 10kA miniature circuit breakers are the premier choice for bulk procurement, offering high-breaking capacity compliant with IEC60898 standards. This MCB is engineered for stable circuit protection in residential and industrial power systems. Featuring a compact flame-retardant design and fast thermal-magnetic tripping, it ensures safety against overloads and short circuits. Easy to install on 35mm DIN rails, it units deliver a long service life and reliable performance for global electrical distributors and contractors.
4.5kA 6kA Miniature Circuit Breaker
CDADA is the professional manufacturer of 4.5kA 6kA Miniature Circuit Breaker, certified with CCC and ISO9001 for safe circuit protection. It uses flame retardant shell and precise thermal-magnetic tripping, is easy to mount on DIN rail and simple to maintain. It combines stable performance with long service life, ideal for residential, commercial and industrial power distribution.
CDADA is a Miniature Circuit Breaker manufacturer and supplier in China. Our factory serves diverse industries such as power systems, building automation, and industrial manufacturing, offering flexible OEM/ODM solutions.
