The Siemens 5SL6340-8CC is a SENTRON 3-pole miniature circuit breaker with a D tripping characteristic, rated 40 A at 400 V AC and a breaking capacity of 6 kA per EN 60898. At 40 A and 3 poles, it covers a 3-phase motor circuit or a distribution subfeed where the upstream breaker is already coordinated.
At 40 °C it derates to 37.72 A, at 45 °C to 36.53 A, at 50 °C to 35.3 A, and at 55 °C to 34.02 A. If the panel runs warm — say, a crowded enclosure with drives — the 40 A frame may need to be bumped to the next size up to stay within the thermal curve.
Mechanical fit and environment
The operating voltage is AC only, 50/60 Hz, with a maximum of 440 V for multi-phase operation. DC rating is limited to 72 V maximum, so it's not a DC distribution breaker. The product designation follows EN 61346-2 and IEC 81346-2 as function letter F.