Overcurrent breaker S 303 3P B 20 A 6000 A DX3 series 407562

Protection of installations and equipment – Legrand S 303 DX3 series overcurrent breaker

This three-pole overcurrent breaker from Legrand’s DX3 series, rated at 20A with characteristic B, provides reliable protection for your electrical installation. Designed with both professional installers and end users in mind, it ensures effective safeguarding against overloads and short circuits. The B characteristic means the breaker responds quickly to short-circuit currents while remaining tolerant to brief current surges—particularly important when connecting devices with motors or transformers.

Construction and application

The S 303 breaker is designed for mounting on a TH35 rail. Its compact 3-module width allows efficient use of space in distribution boards. It supports cable cross-sections from 1.5 mm² to 35 mm² (single-core) or 1.5 mm² to 25 mm² (multi-core), offering installation flexibility. This breaker is suitable for circuits with a rated voltage of 400V and frequency of 50–60 Hz, protecting both equipment and the electrical installation from damage caused by overcurrents. Its rated short-circuit breaking capacity is 6 kA at 400V (compliant with EN 60898) and 10 kA at 400V (compliant with IEC 60947-2), ensuring safety in the event of a fault.

Design features and additional options

The DX3 series breaker stands out for its high-quality construction and thoughtful design. It supports surface mounting and flush mounting and offers optional accessories such as auxiliary contacts and trip units, enhancing functionality and enabling customization to specific needs. The IP20 protection rating guards against accidental contact. Additionally, the breaker features position indicators on the housing, simplifying diagnostics and status monitoring. The rated impulse withstand voltage (Uimp) reaches up to 4 kV, demonstrating high resilience against voltage surges.