Circuit Breakers

Image Part Number Description / PDF Quantity Rfq
9926251006

9926251006

Weidmuller

CIR BRKR MAG-HYDR 6A 120VAC

15054

9926251007

9926251007

Weidmuller

CIR BRKR MAG-HYDR 7A 120VAC

19

BR2D40UC

BR2D40UC

Weidmuller

CB MCB 489 2P D 40A ACDC

888

9926253520

9926253520

Weidmuller

CIR BRKR MAG-HYDR 20A 480VAC

0

BR3D30UC

BR3D30UC

Weidmuller

CB MCB 489 3P D 30A ACDC

773

BR3D2UC

BR3D2UC

Weidmuller

CB MCB 489 3P D 2A ACDC

781

9926251015

9926251015

Weidmuller

CIR BRKR MAG-HYDR 15A 120VAC

2433184

BR2D2UC

BR2D2UC

Weidmuller

CB MCB 489 2P D 2A ACDC

547

SU1D10UC

SU1D10UC

Weidmuller

CB PROTECTOR 1077 1P D 10A ACDC

22209

9129693500

9129693500

Weidmuller

CIR BRKR 15A 250VAC 80VDC

269

BR3D60UC

BR3D60UC

Weidmuller

CB MCB 489 3P D 60A ACDC

541

BR1C6UC

BR1C6UC

Weidmuller

CB MCB 489 1P C 6A ACDC

7378

1278860000

1278860000

Weidmuller

CIR BRKR THRM 250MA 250VAC 65VDC

520

9926251004

9926251004

Weidmuller

CIR BRKR MAG-HYDR 4A 120VAC

206

9926252520

9926252520

Weidmuller

CIR BRKR MAG-HYDR 20A 480VAC

420

1278930000

1278930000

Weidmuller

CIR BRKR THRM 700MA 250VAC 65VDC

5

9926251013

9926251013

Weidmuller

CIR BRKR MAG-HYDR 13A 120VAC

2320

BR1D60UC

BR1D60UC

Weidmuller

CB MCB 489 1P D 60A ACDC

1894

6720005310

6720005310

Weidmuller

CIR BRKR THRM 10A 24VDC SLD SWCH

335

SU1D5UC

SU1D5UC

Weidmuller

CB PROTECTOR 1077 1P D 5A ACDC

78

Circuit Breakers

1. Overview

Circuit breakers are automatic electrical switches designed to protect circuits from damage caused by overloads or short circuits. Unlike fuses, they can be reset after tripping. Modern circuit breakers ensure electrical safety, prevent equipment damage, and maintain system reliability in residential, commercial, and industrial applications.

2. Main Types and Functional Classification

TypeFunction FeaturesApplication Examples
MCB (Miniature Circuit Breaker)Thermal-magnetic protection, <100A ratingResidential wiring, lighting circuits
MCCB (Molded Case Circuit Breaker)Adjustable trip settings, 10-2500A ratingIndustrial machinery, HVAC systems
ACB (Air Circuit Breaker)High fault current interruption, 400-6300A ratingPower distribution in data centers
RCCB (Residual Current Circuit Breaker)Earth leakage protection (5-500mA sensitivity)Outdoor outlets, swimming pool equipment
RCBO (Residual Current Breaker with Overcurrent)Combines overload, short-circuit, and leakage protectionHospital equipment, construction sites

3. Structure and Components

Typical components include: - Enclosure: Flame-retardant insulating material housing - Contacts: Silver alloy for high conductivity - Trip Mechanism: Bimetallic strip (thermal) and electromagnetic coil (magnetic) - Arc Extinguisher: Multi-plate chamber for arc suppression - Operating Lever: Manual ON/OFF control with position indicators

4. Key Technical Parameters

ParameterDescriptionImportance
Rated Current (In)Maximum continuous current without trippingDetermines load capacity
Rated Voltage (Un)Maximum operating voltageEnsures insulation safety
Breaking Capacity (Icu)Maximum fault current interrupting capabilityPrevents catastrophic failure
Tripping CharacteristicsTime-current curve (B/C/D types)Matches load requirements
Pole Number1P to 4P configurationsDetermines phase protection

5. Application Fields

  • Power distribution: Residential panels, commercial switchboards
  • Industrial equipment: Motors, transformers, CNC machines
  • Renewable energy: Solar inverters, wind turbine systems
  • Transportation: EV charging stations, rail traction systems

6. Leading Manufacturers and Products

ManufacturerRepresentative ProductKey Features
Schneider ElectricActi 9 seriesModular design, 0.5-125A range
Siemens5SJ seriesHigh short-circuit withstand, DIN rail mount
ABBEmax seriesSmart connectivity, up to 6300A
General ElectricTHQL seriesUL-certified, industrial motor protection

7. Selection Guidelines

Key considerations: - Match rated current to load requirements (125% safety margin) - Select tripping curve (Type B for resistive loads, C for motors) - Verify breaking capacity against system fault levels - Consider environmental factors (temperature, altitude) - Ensure compliance with standards (IEC 60898, UL 489) - Example: For a 20kW motor (400V), select MCCB with 63A rating, Type C curve, 50kA breaking capacity

8. Industry Trends

Emerging trends include: - Smart grid integration with IoT-enabled monitoring - Compact designs for space-constrained applications - Eco-friendly materials with halogen-free construction - Integration with renewable energy systems - Predictive maintenance via AI-powered diagnostics - Increased adoption of DC circuit breakers for EV infrastructure

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