Circuit Breakers

Part Number	Description / PDF	Quantity
3120-N311-P7T1-W01D-20A E-T-A	CIR BRKR THRM 20A 250VAC 50VDC	8
IULK11-38392-1 Sensata Technologies – Airpax	CIRCUIT BREAKER MAG-HYDR LEVER	0
IEG1-1-72-20.0-91-V Sensata Technologies – Airpax	CIR BRKR 20A 250VAC 80VDC	0
1278930000 Weidmuller	CIR BRKR THRM 700MA 250VAC 65VDC	5
1110-F112-P1M1-3.5A E-T-A	CIR BRKR THRM 3.5A 250VAC 50VDC	0
MOCB-12-N-50A OptiFuse	NO BRACKET-TYPE II MOD, 50A 12V	440
IULK1-1-53-3.00-01 Sensata Technologies – Airpax	CIR BRKR MAG-HYDR 3A LEVER	0
4404.0101 Schurter	CIRC BREAKER PCB MNT 8A	105
3G10UM Altech Corporation	CIR BRKR THRM-MAG 10A LEVER	832
4430.2308 Schurter	CIR BRKR THRM 2A 240VAC 60VDC	20
4435.0314 Schurter	CIR BRKR THRM 5A 240VAC 60VDC	9
4400.0161 Schurter	CIR BRKR THRM 3A 240VAC 48VDC	0
4430.0617 Schurter	CIR BRKR THRM 240VAC 60VDC	20
4400.0141 Schurter	CIR BRKR THRM 700MA 240VAC 48VDC	0
GMB633PC15 Carlo Gavazzi	CIR BRKR THERM-MAG 15A 240VAC	3
9926251013 Weidmuller	CIR BRKR MAG-HYDR 13A 120VAC	2320
4430.3624 Schurter	CIR BRKR THRM 20A 240VAC 60VDC	13
4230-T110-K0BU-2A E-T-A	CIR BRK THRM-MAG 2A 277VAC/60VDC	0
GMB63H3PC1 Carlo Gavazzi	CIR BRKR THERM-MAG 1A 480/277V	3
T11-2-15.0A-01-11 Sensata Technologies – Airpax	CIR BRKR MAG-HYDR 15A TOGGLE	0

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