Siemens 5SY7432-8 — 4-pole D-curve MCB, 32 A, 25 kA
The Siemens 5SY7432-8 is a SENTRON miniature circuit breaker with a 4-pole design (4P) and a D tripping characteristic, rated at 32 A at 35 °C. It provides a breaking capacity of 25 kA per IEC 60947-2 and 15 kA per EN 60898, making it suitable for high-fault-current industrial panels where motor or transformer inrush currents would nuisance-trip a C-curve device.
Ratings and what they mean for fit
The D-curve (tripping characteristic class D) means the magnetic trip operates at 10–20× In, so this breaker holds through the high inrush of motor starting, transformer energization, or welding equipment without dropping out. At 32 A rated current, it handles continuous loads up to that value at 35 °C ambient; derate to 30.46 A at 40 °C, 29.66 A at 45 °C, 28.86 A at 50 °C, 28 A at 55 °C, and 27.14 A at 60 °C per the published curve. Breaking capacity of 25 kA under IEC 60947-2 certifies it can safely interrupt fault currents up to that level in industrial installations (pollution degree 3, overvoltage category III). The 15 kA rating per EN 60898 covers residential and commercial branch-circuit applications. Both ratings are AC only, 50/60 Hz. IP20 protection with connected conductors means it is touch-safe when wired but not sealed against moisture — suitable for enclosed distribution boards, not wet-area standalone mounting.
Panel integration and mounting
Occupies 4 modular width units (72 mm wide) on a DIN rail. Installation depth is 70 mm; overall depth is 76 mm. The quick assembly system (fastening method) snaps onto the rail without tools. Mounting position is any orientation, and the power supply cord position is any — no derating for upside-down or side-mounted installation. Combined terminal top and bottom simplifies busbar and feed-through wiring. Sealable design allows the installer to lock the toggle position with a seal wire or padlock for lockout/tagout compliance. Touch protection (product feature) is built in per the terminal design.