What this MCCB does on the line
The Siemens SENTRON 3VA2125-7HM46-0AA0 is a 4-pole molded case circuit breaker rated for 25 A continuous current, with an adjustable thermal-magnetic trip unit covering 38 A to 300 A. It is designed for line protection in distribution panels and features integral ground-fault monitoring via summation current formation on the L + N conductors. Breaking capacity reaches 330 kA at 240 V AC, dropping to 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.7 kA at 690 V. The rated insulation voltage is 800 V. These figures tell you the fault-current it can safely interrupt at each system voltage — critical for upstream coordination studies. The trip unit is set at the factory for a 15 A pickup and 25 A full-scale value, with no undervoltage release and no communication function. It is a standalone protective device, not a smart breaker.
Panel fit and environment
Dimensions are 86 mm deep, 140 mm wide, and 181 mm high — a standard SENTRON 3VA form factor that fits existing Siemens switchboard and distribution panel cutouts. No rewiring is needed if replacing a same-frame 3VA breaker; the mounting footprint and busbar connections are identical across the series. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Power loss is 0.6 W maximum at rated current — negligible for thermal budgeting inside a sealed enclosure.