Overview
The ABB S201U-K8 is a high-performance miniature circuit breaker (MCB) from ABB’s System pro M compact S200U series. Operating at 240 VAC with an 8 amp rated current and K-curve tripping characteristic, this single-pole unit delivers 10 kA interrupt capacity and thermal-magnetic overcurrent protection. Current-limiting design reduces fault damage and nuisance trips, making it essential for circuits with inductive loads such as motors and transformers.
Key Features
- K-Curve Tripping Characteristic: Delayed thermal mechanism tolerates functional inrush current typical of motors and transformers; electromechanic short-circuit tripping for instantaneous fault protection.
- Current-Limiting Technology: Reduces peak fault current and arc energy, minimizing equipment damage during short circuits.
- DIN Rail Mounting: Compact 17.5 mm wide profile fits standard 35 mm DIN rails for space-efficient panel installation.
- 10 kA Interrupt Capacity: Rated to safely interrupt faults up to 10,000 amps at 240 VAC per UL 489 standard.
- Screw Terminal Connections: Accepts 18 to 4 AWG wire for flexible field wiring compatibility.
- Toggle Actuator: Manual on/off control with mechanical trip indication for easy status verification.
Technical Specifications
- Voltage Rating: 240 VAC
- Rated Current: 8 A
- Trip Characteristic: K-Curve (Thermal-Magnetic)
- Interrupt Rating: 10 kA at 240 VAC
- Number of Poles: 1-Pole
- Frequency: 50/60 Hz
- Mounting: DIN Rail (35 mm standard rail)
- Terminal Type: Screw Terminals
- Wire Gauge: 18 to 4 AWG
- Operating Temperature Range: −25 to +55 °C
- Enclosure Rating: IP20 (Finger-safe)
- Dimensions: 92 mm H × 17.5 mm W × 71 mm D
- Series: S200U (System pro M compact)
Typical Applications
The ABB S201U-K8 is designed for branch circuit protection and control in:
- Industrial motor circuits and variable frequency drive (VFD) protection
- Transformer primary and secondary windings
- Auxiliary control circuits and solenoid loads
- Commercial lighting and HVAC branch circuits
- Process equipment requiring high inrush tolerance with fast short-circuit response
Compatibility & Replacements
Compatible With
- 35 mm DIN rail standard enclosures and distribution boards
- ABB System pro M compact distribution systems
- Industrial control panels and switchboards rated 240 VAC single-phase
- Electrical systems compliant with IEC/EN 60947-2 and UL 489 standards
Replaces / Drop-In Replacement For
- Equivalent to other single-pole K-curve 8A miniature circuit breakers from the S200U series (verify model compatibility with your system integrator before ordering)
Works With
- Standard 35 mm DIN rail mounting systems
- ABB System pro M compact modular architecture
- Manual control circuits and electromechanical control systems
- Low-voltage distribution equipment per UL 489, IEC/EN 60947-2, and CSA 22.2 No. 5 standards


















