High-Quality DC Circuit Breaker Manufacturer

CDADA is a reliable manufacturer and supplier of DC circuit breakers. Our products are high-quality, dependable, and technologically advanced. We specialize in developing tailored solutions for industries such as new energy, providing you with comprehensive, one-stop OEM services.

What Is a DC Circuit Breaker?

A DC circuit breaker is a specialized protective device designed to interrupt direct current (DC) circuits under overload, short-circuit, or fault conditions. Unlike AC circuit breakers that benefit from natural current zero-crossings (100-120 times per second at 50/60Hz), DC breakers must forcibly extinguish a continuous, unidirectional arc that lacks inherent self-extinguishing properties. This fundamental difference necessitates sophisticated arc quenching technologies, making DC breakers physically larger, more complex, and more expensive than their AC counterparts .

DC circuit breakers operate across voltage ranges from 12V to 1500V DC, with current ratings spanning 2A to 2500A. They serve as critical protection components in solar photovoltaic (PV) systems, battery energy storage systems (BESS), electric vehicle (EV) charging infrastructure, data centers with DC power distribution, industrial DC motor controls, and marine electrical systems .

The core challenge in DC interruption lies in arc extinction physics: DC arcs maintain stable plasma columns with temperatures exceeding 10,000°C, requiring forced elongation, cooling, and deionization through magnetic fields, arc chutes, and specialized contact materials .

Product Categories & Configurations

Classification	Type	Current/Voltage Range	Key Characteristics
By Construction	DC MCB (Miniature)	2A – 125A, 250V – 1000V DC	DIN rail mounting, fixed trip settings, residential/commercial PV
	DC MCCB (Molded Case)	10A – 2500A, 500V – 1500V DC	Adjustable trip units, high breaking capacity, industrial/utility
	DC ACB (Air Circuit Breaker)	630A – 6300A, 1000V DC	Draw-out design, electronic protection, power distribution
	Solid-State DC Breaker	100A – 5000A, up to 1500V DC	Semiconductor-based, <1ms operation, no arcing, premium cost
By Voltage Rating	Low Voltage	12V – 250V DC	Automotive, marine, telecommunications
	Medium Voltage (PV Standard)	250V – 1000V DC	Solar PV strings, combiner boxes, residential/commercial
	High Voltage	1000V – 1500V DC	Utility-scale PV, battery storage, EV fast charging
By Pole Configuration	1-Pole	250V DC	Single-string PV, low-voltage DC
	2-Pole (Series)	500V – 750V DC	Mid-voltage PV, dual-pole series connection
	3-Pole	750V DC	Three-phase DC systems, specialized industrial
	4-Pole (Series)	1000V – 1500V DC	High-voltage PV, battery racks, EV infrastructure
By Trip Technology	Thermal-Magnetic	2A – 800A	Bimetallic overload + solenoid short-circuit, economical
	Electronic	100A – 2500A	Microprocessor-based, adjustable curves, communication
	Magnetic Only	10A – 100A	Short-circuit only, motor protection, fast operation

Critical Designation: Polarity Sensitivity DC breakers must be marked with positive (+) and negative (-) terminals, with current direction indicators. Reverse polarity installation can result in catastrophic failure due to asymmetric arc behavior .

Core Functions & Operating Principle

The DC Arc Challenge

Unlike AC arcs that extinguish naturally at current zero-crossings, DC arcs present unique extinguishing challenges:

Parameter	AC Arc	DC Arc
Current waveform	Sinusoidal, zero-crossings every 10ms (50Hz)	Continuous, constant magnitude
Arc voltage	Fluctuates with current	Stable, requires forced extinction
Arc extinction	Natural at zero-crossing	Forced elongation + cooling required
Arc energy	Pulsed, lower average	Continuous, concentrated heat
Contact wear	Moderate	Severe without proper quenching
Required gap	Smaller	2-3× larger for equivalent voltage

Arc Extinction Technologies

Technology	Mechanism	Application	Performance
Magnetic Blowout	Lorentz force F = I × L × B drives arc into splitter plates at 50-200 m/s	Universal for DC MCB/MCCB	Most common, cost-effective, 10-20kA breaking
Arc Chute with Splitter Plates	Arc divided into series segments, cooled, deionized	Standard in all DC breakers	Essential component, voltage drop per plate 30-50V
Permanent Magnets	NdFeB magnets (0.1-0.3T) perpendicular to arc path	Compact DC MCBs	No external power, temperature-stable to 150°C
Electromagnetic Blowout Coil	Self-energized coil generates field proportional to fault current	High-current MCCBs	Force increases with current, adaptive protection
Vacuum Interruption	Arc extinguished in vacuum (no ionizable medium)	High-voltage DC, specialized	Excellent for >1000V DC, long life, expensive
Air Blast	Compressed air cools and stretches arc	High-power industrial, legacy	High maintenance, rarely used in modern designs

Magnetic Blowout Physics

The Lorentz force equation governs DC arc manipulation:

F = I × L × B

Where:

F = Force on arc (Newtons)

I = Arc current (Amperes)

L = Arc length (meters)

B = Magnetic flux density (Tesla)

Example Calculation:

Arc current: 1000A

Arc length: 0.02m (2cm)

Magnetic field: 0.2T

Force: F = 1000 × 0.02 × 0.2 = 4N

Acceleration: a = 4N / (5×10⁻⁴ kg/m × 0.02m) = 400,000 m/s²

This enormous acceleration drives the arc into splitter plates within milliseconds, where it is segmented, cooled, and extinguished.

Application Environments & Use Cases

Industry Sector	Specific Application	Typical Specifications	Critical Requirements
Solar PV (Residential)	String protection, combiner boxes	10A-32A, 250V-500V DC, 2-pole, Type C curve	UV resistance, IP65 enclosure, 20kA Icu
Solar PV (Commercial)	Combiner box main, inverter protection	63A-125A, 500V-1000V DC, 4-pole, 10-20kA Icu	High ambient (60°C), reverse current withstand
Solar PV (Utility)	Central inverter, DC collection	250A-800A, 1000V-1500V DC, DC MCCB, 50kA Icu	Selective coordination, remote monitoring
Battery Energy Storage	Battery rack protection, DC bus	125A-630A, 750V-1500V DC, electronic trip, 4-pole	Bidirectional protection, high short-circuit current
EV Charging	DC fast charger protection, battery interface	200A-400A, 500V-1000V DC, high endurance	Frequent operation, high inrush, SIL 2 safety
Data Centers	380V DC distribution, UPS protection	63A-250A, 380V DC, high breaking, low energy let-through	Minimal downtime, selective coordination
Rail Traction	Metro, tram, railway DC supply	1000A-4000A, 750V-1500V DC, DC ACB	High mechanical endurance, vibration resistance
Marine/Offshore	Ship DC distribution, offshore platforms	100A-400A, 500V DC, corrosion-resistant	Salt spray, tropicalized, redundant tripping

Manufacturing Process & Production Workflow

Precision Manufacturing Sequence

Raw Material IQC → Contact System Fabrication → Arc Chute Assembly → Magnetic System Integration → Mechanism Assembly → Trip Unit Calibration → Primary Assembly → High-Current Testing → Final QC → Packaging

Critical Manufacturing Stages

Stage	Process Details	Quality Control Points
Contact Fabrication	Silver-tungsten (AgW 70/30) or copper-tungsten (CuW 80/20) contact tips, brazing to copper carriers, wiping geometry forming	Hardness HV 120-180, arc erosion resistance, contact resistance <1mΩ, brazing strength >80MPa
Arc Chute Construction	Ceramic splitter plates (6-15 plates depending on voltage), steel arc runners, permanent magnet integration, optimized arc chamber geometry	Dielectric strength >3kV, arc quenching time <10ms, magnetic flux density 0.15-0.25T
Magnetic Blowout System	NdFeB permanent magnet placement (N52 grade), pole piece machining, magnetic circuit optimization, temperature compensation	Flux density ±10% tolerance, temperature coefficient -0.1%/°C, demagnetization resistance
Mechanism Assembly	Quick-make/quick-break toggle, spring energy storage, trip-free linkage, contact pressure springs	Contact opening speed >1.2 m/s, mechanical endurance 20,000 cycles, trip time <20ms
Trip Unit Calibration	Bimetallic thermal element calibration (±5% accuracy), magnetic solenoid gap setting, time-current curve verification	1.05×In no-trip, 1.25×In trip <1h, 5×In instantaneous, data logging
High-Current Testing	Primary injection testing at 10kA-20kA, arc extinction verification, temperature rise measurement	Breaking capacity verification, contact wear <5% after test, dielectric recovery

Primary Raw Materials & Component Specifications

Component	Material Specification	Supplier Standards	Key Properties
Main Contacts	Silver-tungsten (AgW 70/30) or copper-tungsten (CuW 80/20)	ASTM B702, IEC 60368	High arc erosion resistance, anti-welding, conductivity 45-55% IACS
Arc Chute Plates	Alumina ceramic (Al₂O₃ 95%) or steatite	IEC 60672	Heat resistance >1200°C, dielectric strength >15kV/mm, arc quenching
Permanent Magnets	NdFeB N52 (Neodymium-Iron-Boron)	IEC 60404-8-1	Remanence 1.48T, coercivity >1000kA/m, temperature stable to 150°C
Magnetic Pole Pieces	Low-carbon steel 1008 or silicon steel	ASTM A1008	High permeability, low remanence, magnetic flux guidance
Moulded Case	BMC (DMC-2) thermosetting or PA66 GF30	IEC 60664-1, UL 94 V-0	Tracking index >600V, heat resistance 180°C, arc containment
Contact Springs	Beryllium copper (CuBe2) or stainless steel 301	ASTM B196	Fatigue life >50,000 cycles, consistent pressure, corrosion resistance
Terminals	Copper C11000 with tin or silver plating	ASTM B187	Current density 1.5-2.0 A/mm², low contact resistance, oxidation resistance
Bimetallic Elements	Inconel/passivated steel composite	ASTM B388	Deflection rate 0.2mm/°C, stability ±3%, calibration accuracy ±5%
Electronic Components (for electronic trip units)	Industrial-grade PCBs, Hall sensors, ARM processors	IEC 60721-3-3	-25°C to +70°C operation, EMC Level 3, SIL 2 capable

Standards Compliance & Testing Protocols

International Standards Framework

Standard	Scope	Applicable Ratings
IEC 60947-2	Low-voltage switchgear - Circuit-breakers (includes DC)	Universal standard for DC breakers up to 1500V DC
IEC 60898-2	Circuit breakers for DC operation (household)	DC MCBs up to 125A, 220V DC (1-pole), 440V DC (2-pole)
IEC 61643-31	SPDs for photovoltaic applications	DC surge protection coordination with breakers
GB/T 14048.2	Chinese national standard	CCC certification for China market

Critical DC Testing Requirements:

Critical DC load current test: Verification of cut-off current where arcing time increases significantly

Short-circuit breaking capacity: Tested at maximum DC voltage with specified time constant (L/R ratio)

Overload performance: Verification of thermal trip at 1.45×In for 1 hour

Mandatory Type Tests (IEC 60947-2 for DC)

Test Category	Specific Test	Acceptance Criteria
Temperature Rise	Continuous current at rated In	Terminals ≤80K (silver), ≤65K (bare), case ≤40K
Dielectric Properties	Power-frequency withstand (2.5kV-3.5kV/1min), impulse (8kV)	No breakdown, no flashover
Tripping Characteristics	Overload: 1.05×In (no trip), 1.25×In/1.45×In (trip within limits)	Conventional tripping times per curve
	Short-circuit: 5×In, 10×In instantaneous trip	<20ms operation
Operational Performance	Mechanical: 20,000 cycles; Electrical: 10,000 cycles	<5% parameter drift
Short-Circuit Breaking	Icu (ultimate), Ics (service) at rated DC voltage	Successful interruption, no contact welding
Critical DC Load Current	Verification of arcing time limits	No excessive arcing within rated range
Magnetic Blowout Verification	Arc extinction time, arc chamber integrity	<10ms arc duration, no chamber breach
Environmental	Damp heat, cold, dry heat, vibration	Functional after conditioning

Factory Quality Control & Inspection Standards

Incoming Material QC (IQC)

Material	Inspection Items	Sampling Plan	Equipment
Tungsten contact tips	Density, hardness, silver content, dimensional tolerance	Per batch	Spectrometer, hardness tester, CMM
NdFeB magnets	Remanence, coercivity, temperature coefficient, plating	Per batch	Hysteresisgraph, Helmholtz coil
Ceramic plates	Dielectric strength, thermal shock resistance, dimensions	Per batch	Dielectric tester, thermal shock chamber
Copper carriers	Conductivity, hardness, plating thickness	Per batch	Conductivity meter, micrometer, XRF
Thermosetting plastic	Glass content, viscosity, cure time, flammability	Per batch	DSC, melt flow indexer, UL 94 apparatus

In-Process Quality Control (IPQC)

Station	Control Parameters	Frequency	Method
Contact brazing	Temperature 800-850°C, atmosphere, joint strength	Every 100 units	Thermocouple, shear tester, metallography
Magnet placement	Polarity verification, flux density, alignment	Every unit	Flux meter, vision system
Arc chute assembly	Plate spacing, magnet alignment, runner geometry	Every 50 units	Go/no-go gauges, flux density mapping
Mechanism calibration	Opening speed, contact pressure, trip force	Every unit	High-speed camera, force gauge, automated bench
Trip unit testing	Time-current curve, instantaneous trip, ambient compensation	Every unit	Primary injection tester (10,000A), data logging

Final Quality Control (FQC) & Outgoing QC (OQC)

Test Item	Standard	Sample Size
Polarity marking verification	Correct +/-/current direction marking	100%
Contact resistance	<1mΩ per pole	100%
Dielectric withstand voltage	2.5kV AC/1min	100%
Insulation resistance	>100MΩ @ 500V DC	100%
Tripping characteristics	1.05×In, 1.25×In, 5×In, 10×In verification	100%
Magnetic blowout function	Arc extinction test at rated current	100%
Mechanical operation	10 ON-OFF cycles, smooth operation	100%
Visual & dimensional inspection	Clearance, creepage, marking permanence	100%
High-current sampling	Breaking capacity verification (10kA)	AQL 0.65
Packaging integrity	Drop test, vibration (ISTA 3A)	Per lot

Production Infrastructure & Manufacturing Capability

Advanced Production Equipment

Equipment Category	Machine Specification	Function	Capacity
Contact Fabrication	Vacuum brazing furnace (10⁻³ mbar, 900°C)	Tungsten-silver contact brazing	5,000 contacts/day
Magnet Assembly	Automated magnet placement with polarity detection	NdFeB magnet integration, flux verification	3,000 assemblies/day
Arc Chute Production	Ceramic plate pressing, firing, metallization	Splitter plate manufacturing	10,000 plates/day
Mechanism Assembly	Labor assembly cells	High-speed assembly, calibration	2,000 units/day per line
Testing Equipment	Primary injection test set (20,000A DC capacity)	High-current trip verification	300 units/day
	Arc extinction test chamber (high-speed imaging)	Arc behavior analysis, blowout verification	50 units/day
	Environmental test chamber (temperature, humidity, vibration)	IEC 60068-2 compliance	100 units/day

Production Capacity & Lead Times

Product Category	Monthly Capacity	Standard Lead Time	Urgent Order Capability
DC MCB 1P/2P (10A-63A, 250V-500V)	200,000 units	4-5 weeks	5 days
DC MCB 4P (63A-125A, 1000V)	100,000 units	4-5 weeks	7 days
DC MCCB (125A-400A, 500V-1000V)	30,000 units	4-5 weeks	10 days
DC MCCB (630A-1600A, 1000V-1500V)	10,000 units	4-5 weeks	2 weeks
High-voltage DC (1500V+, specialized)	Project basis	8-12 weeks	4 weeks

Engineering & Technical Team Structure

Department	Personnel	Expertise	Responsibilities
R&D Engineering	5 engineers	DC arc physics, magnetic field simulation, contact materials, power electronics	New DC breaker development, patent portfolio (35+ patents), HVDC innovation
Process Engineering	20 engineers	Vacuum brazing, magnet assembly, ceramic processing, automation	Production optimization, yield improvement (>98%), Industry 4.0 integration
Testing & Validation	15 engineers	High-current DC testing, arc extinction analysis, environmental simulation, EMC	Type testing coordination (IEC 60947-2), failure analysis, certification
Application Engineering	12 engineers	Solar PV design, battery storage systems, EV charging, DC microgrids	Customer technical support, system design, selective coordination
Quality Assurance	30 technicians	ISO 9001, ISO 14001, statistical process control, metrology laboratory	Supplier audit, process audit, corrective action, calibration management

Why Our DC Circuit Breaker Manufacturing Stands Apart

Our production facility represents 15 years of specialization in DC circuit protection, delivering breakers that exceed global standards through:

Arc physics expertise: Proprietary magnetic blowout designs with optimized Lorentz force geometry, achieving <10ms arc extinction at 1500V DC

Vertical integration: In-house tungsten-silver contact brazing, NdFeB magnet assembly, and ceramic arc chute manufacturing ensuring complete quality control

Testing infrastructure: $4M+ invested in high-current DC laboratories capable of 20,000A interruption testing, arc extinction high-speed imaging (100,000 fps), and environmental simulation

Renewable energy focus: Specialized designs for solar PV (1000V-1500V), battery storage (bidirectional protection), and EV charging (high inrush withstand)

Solid-state innovation: Development of semiconductor-based DC breakers for <1ms operation in critical battery protection applications

For technical specifications, solar PV protection coordination, battery storage system design, or factory audit scheduling, our engineering team provides direct consultation to ensure your DC power systems meet both safety requirements and operational reliability objectives.

CDADA is a DC 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.

News Recommendations