Siemens Miniature circuit breaker, 2-pole, 25kA, 400V, Ø70mm Part number 5SY8225-8

Product Overview

The Siemens 5SY8225-8 is a two-pole (2P) miniature circuit breaker from the SENTRON 5SY8 series. It is rated for 25 A, has a D-curve tripping characteristic, and is designed for industrial and infrastructure applications requiring high breaking capacity (25 kA at 400 V AC according to EN 60947-2). Its compact 70 mm depth housing, robust mechanical design and high fault-current resilience make it ideal for demanding switchboard and motor feeder protection systems.

Key Features

• 2-pole (2P) miniature circuit breaker
• Rated current: 25 A
• Tripping characteristic: D-curve (suitable for loads with high inrush currents)
• Rated operational voltage (AC): 400 V; insulation voltage: 440 V
• Breaking capacity: up to 30 kA (AC) according to IEC/EN 60947-2
• Compact installation depth (~70 mm) for space-efficient switchgear design
• Halogen-free and sealable version for industrial safety requirements
• Touch protection for main terminals and combined top/bottom terminals for flexible wiring

Technical Specifications

• Article Number: 5SY8225-8
• Series: SENTRON 5SY8
• Number of Poles: 2 (2P)
• Rated Current (AC-3, 40 °C): 25 A
• Rated Supply Voltage (AC): 400 V
• Insulation Voltage (Ui): 440 V AC
• Breaking Capacity (Icu): 25 kA at 400 V AC (25 kA typical); rating up to ~30 kA per catalogue data
• Tripping Characteristic: D-curve
• Module Width: Approx. 36 mm (2 modules wide on DIN rail)
• Housing Depth: ~70 mm
• Ambient Operating Temperature: –25 °C to +55 °C
• Protection Class (Front): IP20 with terminals connected

Compliance & Certifications

• Designed in accordance with IEC/EN 60947-2 and related circuit-breaker standards
• Tested for industrial switchgear applications, suitable for high fault-current environments
• Halogen-free and sealable options meet enhanced safety and environmental requirements

Applications

This miniature circuit breaker is ideally suited for industrial and infrastructure electrical installations, where branch-circuit protection or motor-feeder protection is needed with high fault-current capacity and reliable performance. Thanks to its D-curve trip characteristic, it is particularly appropriate for circuits with high inrush currents—such as motors, transformers and large capacitive loads—while still offering compact form-factor advantages for panel installation.