Siemens 5SY8301-7 — 3-pole C-curve MCB, 70 kA breaking capacity
The Siemens 5SY8301-7 is a 3-pole miniature circuit breaker from the SENTRON family, with a C-curve trip characteristic and a rated breaking capacity of 70 kA at 400 V AC per IEC 60947-2. For DC circuits it carries a 15 kA rating at 60 V per IEC 60947-2, and under UL 1077 it is listed at 5 kA — so the same part works in IEC-spec panels and UL-recognized supplementary protection applications, though the UL rating is lower and governs the North American installation limit.
Panel fit and environmental tolerance
The 5SY8301-7 occupies 3 modular width units (54 mm) on a DIN rail, with a depth of 76 mm and an installation depth of 70 mm. It mounts in any position, and the quick-assembly fastening system clips onto the rail without tools — standard for SENTRON MCBs. Ambient range spans -40 °C to 75 °C, with humidity tolerance up to 95% at 55 °C, derating to 35% at 75 °C. Vibration resistance per IEC 60068-2-6 is ±1 mm at 5–25 Hz and 50 m/s² at 25–150 Hz, so it holds up in machine-mounted panels on conveyors or compressors.
The terminals accept supply from either top or bottom, and the unit is sealable for tamper-evident installations.