Siemens 5SY8425-8 SENTRON MCB — 4-pole, 25 A, D curve, 30 kA
The Siemens 5SY8425-8 is a 4-pole miniature circuit breaker from the SENTRON family, rated 25 A at AC with a D tripping characteristic and a breaking capacity of 30 kA per IEC 60947-2.
Rated 25 A at 45 °C ambient, the 5SY8425-8 derates to 24.38 A at 50 °C and 23.72 A at 55 °C — per the datasheet, the thermal-magnetic trip element is calibrated to the 45 °C reference. The DC breaking capacity is 15 kA per IEC 60947-2, which covers most industrial DC bus applications; the UL 1077 / CSA C22.2 No.235 rating is 5 kA, so for North American supplementary protection installations the available fault current must stay under that limit.
Touch protection is integrated per the product feature listing.
Vibration resistance per IEC 60068-2-6: ±1 mm at 5 to 25 Hz, 50 m/s² at 25 to 150 Hz. The sealable design allows lockout/tagout in safety circuits.