The Siemens SENTRON 5SL6150-7BB is a 1-pole miniature circuit breaker with a C tripping characteristic, rated 50 A at 400 V AC. Its 6 kA breaking capacity per EN 60898 and IEC 60947-2 covers most residential and light commercial fault levels — enough for a standard distribution board but not for high-fault industrial switchgear. The 18 mm width (1 MW) fits standard DIN-rail enclosures; depth is 76 mm, which is typical for this class and leaves clearance for wiring in a 100 mm deep panel.
C-curve means the magnetic trip activates at 5–10× In (250–500 A), so it handles motor inrush and transformer energization better than a B-curve but still clears fast on a hard short. The 50 A rating is the continuous thermal current at 30 °C ambient; above 45 °C you derate per the manufacturer's curve. Terminal capacity accepts solid or stranded copper up to 25 mm² — enough for a 50 A feed without pigtailing down. Tightening torque is 2.5–3 N·m, which is standard for this terminal size.