Siemens 5SY41045 MCB 1-Pole 4A C-Curve 6kA 230/400V AC

Protect your electrical circuits from overload and short-circuit damage with the Siemens 5SY41045 miniature circuit breaker (MCB). This 1-pole device is rated for 4 A with a C tripping characteristic, making it suitable for general lighting and socket circuits with moderate inrush currents.

Who is it for

Electricians, panel builders, and facility maintenance professionals who need a reliable DIN-rail mounted MCB for distribution boards in residential, commercial, or light industrial installations.

Main features

• 1-pole (1P) design, 1 module width (18 mm) for space-saving installation.
• Rated current 4 A, C-curve for protection against overload and short-circuit.
• Rated voltage 230/400 V AC, 50/60 Hz.
• Rated breaking capacity 6 kA according to IEC/EN 60898-1.
• Screw terminals accept conductors up to 35 mm² (solid/stranded) or 25 mm² (fine-stranded).
• Mounts on standard DIN rail EN 60715.
• Electrical endurance 10,000 cycles, mechanical endurance 20,000 cycles.

Specifications

• Number of poles: 1P
• Rated current: 4 A
• Tripping characteristic: C
• Rated voltage: 230/400 V AC
• Rated frequency: 50/60 Hz
• Rated switching capacity (Icn): 6 kA
• Mounting type: DIN rail (EN 60715)
• Terminal type: Screw terminals
• Max. conductor cross-section (solid/stranded): 0.75 - 35 mm²
• Max. conductor cross-section (fine-stranded): 0.75 - 25 mm²
• Degree of protection: IP20 (terminals), IP40 (with enclosure)
• Electrical endurance: 10,000 switching cycles
• Mechanical endurance: 20,000 switching cycles
• Standard: IEC 60898-1, EN 60898-1
• Module width: 1 TE (18 mm)
• Operating temperature: -25 to +45 °C
• Storage temperature: -40 to +75 °C
• Overvoltage category: III

Tips

Ensure the MCB's rated current and tripping curve match the load characteristics. For circuits with high inrush currents (e.g., motors, transformers), consider a D-curve breaker. Always de-energize before installation and verify torque settings on screw terminals.