What it is and what it does
The Siemens 3VA1025-4ED32-0HC0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection in distribution panels. It is a 3-pole unit rated 25 A continuous at 40 °C, with a breaking capacity of 121 kA at 240 V AC — that figure drops to 75.6 kA at 415 V and 52.5 kA at 440 V, so the SCCR you need for the fault-current study determines which voltage column governs the install. The breaker carries a shunt trip (STL) release and two auxiliary switches HQ, factory-fitted. The shunt trip lets a remote signal (e.g., emergency-stop relay or fire-alarm panel) open the breaker without a manual trip. The auxiliary switches report the main-contact position back to a PLC or status lamp.
Sizing and thermal derating
The 25 A rating holds flat from 40 °C through 50 °C. At 55 °C it derates to 24 A, and at 70 °C it is 23 A. For a panel that runs hot — say 55 °C ambient inside the enclosure — the breaker still carries 24 A continuous, which is 96 % of the nameplate. That is a shallow derating curve typical of SENTRON 3VA; you do not need to oversize for a warm cabinet unless the load is right at the limit.
Physical fit and panel integration
Dimensions are 130 mm high, 76.2 mm wide, 70 mm deep. It mounts on a DIN rail or can be screw-fixed to a backplate. The 76.2 mm width (3 inches) is standard for a 3-pole MCCB in this frame size; it occupies one 3-module position on a DIN-rail assembly. Depth of 70 mm means it clears most 200 mm-deep enclosures with room for wiring gutters.