The Siemens 5SL4420-6 is a 4-pole miniature circuit breaker from the SENTRON family, with a B tripping characteristic rated 20 A at 30 °C (18.94 A at 40 °C, 17.24 A at 55 °C). It breaks fault currents up to 10 kA per both EN 60898 and IEC 60947-2 at 400 V AC, and carries a maximum 440 V AC in multi-phase operation. The 4 MW (72 mm) width and 76 mm depth mean it occupies four standard 18 mm DIN-rail slots — a common footprint for a 4P residential or light-commercial distribution board. With a mechanical service life of 10 000 operating cycles and an IP20 rating (with connected conductors), this is a standard panelboard MCB for residential buildings and infrastructure, not a motor-protection or high-inrush device.
The 70 mm installation depth (76 mm overall) clears most shallow gland plates. Degree of pollution 2 and overvoltage category III are standard for fixed-installation distribution boards. Touch protection is provided on the line-side terminals. Temperature derating is published: at 40 °C the rated current drops to 18.94 A, at 45 °C to 18.4 A, and at 55 °C to 17.24 A. The maximum operating temperature is 75 °C; minimum is -40 °C, which covers cold-chain and outdoor telecom shelters.
The product function includes neutral conductor switching: no — this is a 4-pole breaker that switches all four poles, but the neutral is not switched separately (it is a 4P, not a 3P+N with a switched neutral).