Circuit Breakers

Part Number	Description / PDF	Quantity
2907505 Phoenix Contact	CIR BRKR 4A 480VAC 125VDC	32
4430.2309 Schurter	CIR BRKR THRM 15A 240VAC 60VDC	475
CBW57-ES-7A-5H OptiFuse	CIR BRKR THRM 7A 250VAC 32VDC	1994
IULK11-28292-2 Sensata Technologies – Airpax	CIRCUIT BREAKER MAG-HYDR LEVER	0
R21-2-16.0A-R02CH-V Sensata Technologies – Airpax	CIR BRKR MAG-HYDR 16A ROCKER	0
GMB63H1PC30 Carlo Gavazzi	MCB HV UL489 C 1P 30A LUG T	18
4430.1708 Schurter	CIR BRKR THRM 10A 240VAC 60VDC	0
LELK1-1RS4-30452-20 Sensata Technologies – Airpax	CIR BRKR MAG-HYDR LEVER	1
3G30UM Altech Corporation	CIR BRKR THRM-MAG 30A LEVER	412
MOCB2-PL2-40A OptiFuse	FUSE FOOTPRINT CB-TYPE II , 40A	0
4230-T120-K0CE-20A E-T-A	CIR BRKR THERM 20A 480VAC/125VDC	0
106-M2-P30-0.05A E-T-A	CIR BRKR THRM 50MA 250VAC 48VDC	0
BR3D60UC Weidmuller	CB MCB 489 3P D 60A ACDC	541
AA1-B0-34-615-1B1-C Carling Technologies	CIR BRKR 15A 277VAC 80VDC	0
4404.0105 Schurter	CIRC BREAKER PCB MNT 15A	4659300
104-PR3-2A E-T-A	CIR BRKR THRM 2A 250VAC 48VDC	0
C25A2P-489 American Electrical, Inc.	CIR BRKR MAG-HYDR 25A 240VAC	0
4411.0214 Schurter	CIR BRKR THRM 3A 277VAC 28VDC	14
2DU4L Altech Corporation	2DU4L4.0A MCBDCHAR2P 480Y/277VAC	412
0903039 Phoenix Contact	CIR BRKR SOLID STATE 12A 24VDC	1

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

Type	Function Features	Application Examples
MCB (Miniature Circuit Breaker)	Thermal-magnetic protection, <100A rating	Residential wiring, lighting circuits
MCCB (Molded Case Circuit Breaker)	Adjustable trip settings, 10-2500A rating	Industrial machinery, HVAC systems
ACB (Air Circuit Breaker)	High fault current interruption, 400-6300A rating	Power 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 protection	Hospital 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

Parameter	Description	Importance
Rated Current (In)	Maximum continuous current without tripping	Determines load capacity
Rated Voltage (Un)	Maximum operating voltage	Ensures insulation safety
Breaking Capacity (Icu)	Maximum fault current interrupting capability	Prevents catastrophic failure
Tripping Characteristics	Time-current curve (B/C/D types)	Matches load requirements
Pole Number	1P to 4P configurations	Determines 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

Manufacturer	Representative Product	Key Features
Schneider Electric	Acti 9 series	Modular design, 0.5-125A range
Siemens	5SJ series	High short-circuit withstand, DIN rail mount
ABB	Emax series	Smart connectivity, up to 6300A
General Electric	THQL series	UL-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