What it is and what it does
The Siemens 5SY4301-7CV is a 3-pole miniature circuit breaker (MCB) with a C tripping characteristic, rated 1 A at 35 °C and 50/60 Hz AC. It is designed for branch-circuit protection in industrial control panels and mechanical engineering applications, per IEC / EN 60947-2. The 15 kA breaking capacity at 440 V AC means it can safely interrupt a fault current up to that level without upstream damage — sized for high-fault installations like machine-tool feeders or distribution sub-panels.
Mounting and panel fit
Snaps onto DIN rail via the quick-assembly system; mounting position any, so it fits vertical or horizontal bus runs. Occupies 3 modular width units (MWU), each 18 mm — total 54 mm wide. Depth 76 mm (installation depth 70 mm) leaves clearance for wiring behind the gland plate. Combined terminals top and bottom accept supply from either end.
Thermal derating and environment
Rated 1 A at 35 °C; derates to 0.93 A at 40 °C, 0.89 A at 45 °C, and 0.8 A at both 50 °C and 55 °C. Ambient operating range -40 °C to 75 °C, with humidity influence capped at 95% up to 55 °C, tapering to 35% at 75 °C. Pollution degree 3 (conductive pollution) and overvoltage category III suit it for industrial environments where condensation or dust is present. Halogen-free and silicon-free construction avoids outgassing issues in sealed enclosures.