Siemens 5SY8308-8 — D-curve MCB for motor and transformer branch protection
The 8 A rating holds at 45 °C ambient; at 50 °C it derates to 7.75 A, and at 55 °C to 7.5 A — factor that into the panel thermal budget if the enclosure runs warm.
Fastening is via the quick-assembly system — snaps onto the rail without tools.
DC and AC ratings
On DC circuits the breaking capacity is 15 kA at up to 72 V (per IEC 60947-2). The supply frequency is 50/60 Hz. The part is halogen-free and silicon-free, sealable, and suitable for mechanical engineering and industry environments.