Siemens 5SY4401-7 SENTRON miniature circuit breaker, 4-pole, 1 A rating, C-trip curve. It's the line-side protection for small three-phase loads like control transformers or VFD inputs where the fault level stays under 35 kA. Track which standard governs your panel — the UL1077 listing gives an additional commercial equipment path. At 40 °C ambient, the 1 A rating knocks down to 0.95 A; at 60 °C it's 0.85 A. If the panel runs hot, size up one frame or account for the curve.
Mounting and Installation
Mounts in any position; quick assembly system clips in without tools. IP20 with connected conductors — protect from direct contact but not from moisture.
This is a current-production item. Place against a BOM line — I'll quote to order. No neutral switching on this 4-pole; the fourth pole is the switched phase only — verify if your panel expects a switched neutral.