DC-rated MCB for 440 VDC circuits — 2-pole C-curve at 3 A
The Siemens SENTRON 5SY5203-7CC is a 2-pole miniature circuit breaker rated for DC circuits up to 440 V with a 10 kA interrupting capacity per IEC 60947-2. The C-curve (tripping characteristic class C) means it handles moderate inrush currents — typical for motor control, solenoid valves, or DC power supplies — without nuisance trips, while still clearing short circuits fast. At 3 A it protects downstream wiring and loads on a 440 VDC bus, common in photovoltaic arrays, battery banks, or industrial DC drives.
The 2-pole design switches both conductors, which is required for DC circuits where polarity matters (the evidence notes polarity consideration). The C-curve trips between 5× and 10× rated current, so a 3 A breaker holds through a 15–30 A inrush before opening on overload.
Halogen-free and silicon-free construction avoids corrosive off-gassing in sealed enclosures. Vibration resistance per IEC 60068-2-6 covers ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz — suitable for machine-mounted panels. The sealable design allows lockout/tagout for maintenance isolation.