The Siemens 5SJ6508-7FC is a SENTRON miniature circuit breaker (MCB) rated 8 A at 230 V AC, with a C tripping characteristic and a 6 kA breaking capacity per EN 60898.
Temperature derating matters for panel design
At 30 °C ambient the breaker carries its full 8 A; at 40 °C it derates to 7.39 A, and at 45 °C to 7.04 A. If the panel runs warm — common in enclosed DIN-rail assemblies — size the upstream load so continuous current stays under the derated figure to avoid nuisance tripping.
Mounting and footprint
The housing is 36 mm wide (2 MW), 76 mm deep, 90 mm tall, with an installation depth of 70 mm behind the panel face. Mounting position is unrestricted — horizontal, vertical, or inverted — so it fits tight enclosures without derating. Neutral conductor switching is integrated (the N pole opens and closes with the line pole), which is required in many national wiring rules for single-phase final circuits.