The Siemens 5SL3150-7MB is a SENTRON miniature circuit breaker (MCB) — a 1-pole unit with a C tripping curve, rated 50 A at 230/400 V AC, and a breaking capacity of 4.5 kA per EN 60898. It occupies a single modular width (18 mm) on a DIN rail, so panel density is straightforward: one pole per 18 mm slot.
At higher ambient temperatures, derate per the manufacturer's curve — the maximum ambient is 75 °C, but the breaker's thermal-magnetic trip element responds to both current and heat, so a panel running at 50 °C ambient should not be loaded to the full 50 A continuously. The 4.5 kA breaking capacity (per EN 60898) means it can safely interrupt a fault current up to 4.5 kA at 230/400 V without welding contacts or failing catastrophically. For installations where the prospective short-circuit current exceeds 4.5 kA, a higher-rated upstream device (e.g., an SENTRON 5SL6 series with 6 kA or 10 kA) is needed for coordination. Voltage limits: single-phase operation at 250 V AC, multi-phase at 440 V AC maximum. The DC rating maxes out at 72 V — this is an AC-optimized breaker; for DC circuits above 72 V, look at a DC-rated MCB like the 5SY series.
Dimensions: 18 mm wide (1 modular unit), 90 mm tall, 76 mm deep. Installation depth is 70 mm — that's the space needed behind the DIN rail for the breaker body and wiring. Touch protection is built in — the terminals are shrouded to prevent accidental contact when the breaker is mounted in a panel.