Siemens 3VA1225-5FF42-0DH0 — 125 A SENTRON MCCB for Line Protection
The Siemens 3VA1225-5FF42-0DH0 is a SENTRON molded case circuit breaker (MCCB) rated at 125 A continuous, with 4 poles, designed for line protection in distribution panels. Its interrupting capacity reaches 187 kA at 240 V, 121 kA at 415 V, and 75.6 kA at 440 V — figures that govern selectivity coordination with downstream breakers. The 800 V rated insulation voltage confirms it for 690 V line-to-line systems common in industrial motor control centers.
Thermal Derating and Power Loss
The breaker carries 250 A up to 50 °C ambient, then derates linearly: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C (–). Maximum power loss is 59.5 W — relevant for enclosure heat-rise calculations when grouping multiple breakers in a panel. Operating temperature range is -25 °C to 70 °C (–); storage range is -40 °C to 80 °C (–).
Auxiliary Switching and Releases
Factory-fitted with 2 auxiliary switches plus 1 trip alarm switch (HQ type), and an undervoltage release (UVR). The trip indicator provides local visual status. The basic switch variant is 3VA12255FF420AA0. No communication function or ground-fault monitoring is included.