DC-rated MCB for 50 A circuits
The Siemens SENTRON 5SY5250-6CC is a 2-pole DC miniature circuit breaker rated 50 A with a B tripping characteristic, built for 440 V DC systems and a 10 kA interrupting capacity per IEC 60947-2. That 10 kA rating at 440 V DC means it can safely clear a bolted fault on a battery bank or rectifier bus without letting the arc sustain — a real concern on DC circuits where arcs don't have a natural zero-crossing to self-extinguish. The B curve (3-5 In) trips fast on moderate overloads, which suits resistive loads like heaters, lighting, or control power supplies where you don't want nuisance trips from inrush.
Panel fit and environmental tolerance
At 36 mm wide (2 modular width units) and 76 mm deep, this breaker snaps onto a standard DIN rail via the quick assembly system and can be mounted in any position — handy when you're packing a tight DC distribution panel. The IP20 rating (with connected conductors) means it's protected against finger contact but not washdown; keep it inside a sealed enclosure if there's coolant mist or steam in the air. It's halogen-free and silicon-free, so outgassing won't foul sensitive contacts or optics in the same cabinet. The -40 °C to 75 °C operating range covers cold warehouse startups and hot summer days inside a non-climate-controlled panel.