Siemens 5SY5432-7CC — 4-pole C-curve MCB for DC branch circuits
The Siemens 5SY5432-7CC is a 4-pole miniature circuit breaker from the SENTRON series, with a C-curve trip characteristic rated 32 A at 35 °C and a DC breaking capacity of 10 kA per IEC 60947-2. This is the part you spec when you need a single-module-width (4 MW) DC-rated MCB for a 4-wire circuit — common in industrial control panels feeding DC busbars, UPS outputs, or PV combiner boxes where polarity matters and neutral switching is not required.
The C-curve means the magnetic trip activates at 5–10× In — so at 32 A, instantaneous trip is between 160 A and 320 A. For AC circuits under UL 1077, the rating drops to 5 kA — still adequate for most supplementary-protection roles in a panel. Thermal derating is baked into the datasheet: 32 A at 35 °C, 30.4 A at 40 °C, 29.57 A at 45 °C, 28.74 A at 50 °C, 27.84 A at 55 °C (–). If your panel ambient runs 50 °C, plan for 28.7 A continuous — not the 32 A label.