What this 2-pole D-curve MCB is for
The Siemens 5SJ4208-8HG42 is a 2-pole miniature circuit breaker from the SENTRON 5SJ4 series, sized at 2 modular width units (36 mm) for standard DIN-rail enclosures. Rated 10 kA breaking capacity per EN 60898 and 15 kA per IEC 60947-2 at 400 V AC, with a 60 V DC rating for control-circuit protection. The 440 V insulation voltage (Ui) and overvoltage category 3 with pollution degree 3 mean it's rated for fixed-installation panels in industrial environments — not just residential distribution boards.
Sealable, halogen-free, silicon-free construction — relevant for clean-room or corrosive-gas environments where outgassing matters. Vibration resistance tested to 50 m/s² at 25–150 Hz and 60 m/s² at 35 Hz (4 s), so it holds up on machine-mounted subpanels near rotating equipment.
Listed as current-production lifecycle stage — no phase-out notice on this order code. The 5SJ4 series remains an active Siemens SENTRON line, so BOM freeze risk is low for new builds.