Siemens 5SL4303-8 — SENTRON 3-Pole D-Curve MCB, 3 A, 10 kA
The Siemens 5SL4303-8 is a SENTRON miniature circuit breaker (MCB) with three poles, a D tripping characteristic, and a rated current of 3 A at 400 V AC. Its 10 kA breaking capacity is certified under both EN 60898 and IEC 60947-2, meaning it can safely interrupt fault currents up to that level in residential and infrastructure installations.
At 30 °C ambient the 5SL4303-8 carries its full 3 A rating. At 40 °C it derates to 2.88 A; at 55 °C to 2.69 A — a consideration for densely packed enclosures where internal temperature rise is significant. The breaker occupies 3 modular width units (54 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. Mounting position is unrestricted, and the IP20 protection class (with connected conductors) is standard for enclosed panel use.
Mechanical and environmental ratings
Rated for 10,000 mechanical operating cycles typical. Ambient temperature range -40 °C to +75 °C, with up to 95% humidity at 55 °C.