What this 4-pole D-curve MCB does on the panel
The Siemens 5SL4403-8 is a 4-pole miniature circuit breaker from the SENTRON 5SL series, rated 3 A with a D tripping characteristic. It protects circuits against overload and short-circuit, with a breaking capacity of 10 kA per EN 60898 and IEC 60947-2. Rated for 400 V AC multi-phase operation, with a maximum of 440 V AC. It occupies 4 width units (72 mm) on a DIN rail, installs in any mounting position, and is rated IP20 with conductors connected — standard for enclosed distribution boards.
The 5SL4403-8 is designed for residential buildings and infrastructure applications. It carries touch protection and is sealable, suitable for metering or tamper-proof installations.
Terminal and environmental specs
Screw terminals accept solid or stranded conductors from 0.75 to 25 mm², with a tightening torque of 2.5 to 3 N·m. The breaker is halogen-free and silicon-free, and operates in ambient temperatures from -25 to +55 °C with up to 95% humidity. Installation depth is 70 mm; overall dimensions are 72 mm wide, 90 mm high, and 76 mm deep.