The Siemens 5SY4401-7CV is a 4-pole miniature circuit breaker (MCB) with a C-trip curve rated at 1 A. Its 15 kA breaking capacity (Icu) at 400 V AC means it can safely interrupt fault currents up to that level without welding or arcing over — critical for panel coordination where the upstream device expects a clean fault clearance. The C-curve (5–10× In) suits it for moderate inrush loads like small motor starters or contactor coils, not purely resistive circuits.
Snap-on mounting to a DIN rail (EN 60715) for panel integration. The 4-pole format occupies four modular width units (4 × 18 mm) in the distribution board.