Siemens Miniature circuit breaker, 3-pole, C-curve, 400V, 10kA, 40A Part number 5SY4340-7

Product Overview

The Siemens 5SY4340-7 is a Siemens SENTRON 5SY4 miniature circuit breaker, 3-pole, 40 A, with tripping characteristic C and 10 kA breaking capacity. It delivers reliable overload and short-circuit protection for three-phase AC installations, making it suitable for distribution boards, motor circuits, machinery panels and general electrical installations requiring robust circuit protection.

Key Features

• Three-pole miniature circuit breaker (3P)
• Rated current: 40 A
• C-characteristic — suitable for circuits with moderate inrush currents and mixed loads
• Rated operational voltage: 400 V AC (also compatible with 230/400 V systems)
• Breaking capacity: 10 kA
• Screw-type terminals for secure conductor connections
• Modular width of 3 modules — compatible with standard DIN-rail mounting
• Touch-safe terminal design with halogen-free insulating materials
• Suitable for industrial and commercial power distribution and motor protection applications
• Mechanical service life rated for long-term use with many switching cycles

Technical Specifications

• Article Number: 5SY4340-7
• Poles: 3 (3-Pole)
• Rated Current (In): 40 A
• Tripping Curve: C characteristic
• Rated Voltage (AC): 400 V
• Short-Circuit Breaking Capacity (Icu): 10 kA
• Terminal Connection: Screw terminals for conductor cross-section 0.75 … 35 mm² (depending on wiring standard)
• Mounting: DIN-rail (35 mm) installation
• Protection Rating: IP20 (with connected conductors)
• Mechanical Durability: Approx. 10,000 switching cycles (typical for 5SY4 series)
• Operating Voltage Frequency: 50 / 60 Hz
• Pollution Degree / Overvoltage Category: Pollution degree 3, Overvoltage category III
• Ambient Operating Temperature (standard): –40 °C to +70 °C (depending on installation environment) — typical for 5SY4 series

Compliance & Certifications

• Part of Siemens SENTRON 5SY4 miniature circuit breaker family
• Manufactured to comply with international standards for low-voltage circuit protection devices
• Suitable for use in residential, commercial and industrial installations where reliable branch-circuit protection is required

Applications

The 5SY4340-7 is well suited for protecting three-phase branch circuits in distribution boards, machine control panels, motor feeders, lighting and power circuits, or other industrial installations where a 40 A protection level is needed. Its robust design and modular form factor make it appropriate for both new installations and retrofit applications in commercial or industrial electrical systems.