The Siemens SENTRON 3VA2125-7HL36-0AA0 is a 3-pole molded case circuit breaker (MCCB) rated for 25 A continuous current with an ETU320 electronic trip unit. Its 330 kA breaking capacity at 240 V means it can safely interrupt very high fault currents on a 240 V line without upstream cascading — useful for high-available-fault-current panels like main switchboards or large distribution boards.
Breaking capacity and trip unit
The ETU320 is a basic electronic overcurrent release with adjustable long-time pickup (Ir) and long-time delay (tr). Ir is adjustable from 0.5 to 17 seconds, and the rated continuous current Iu is fixed at 25 A. The trip unit is line-protection only — no ground-fault or communication functions on this version. Breaking capacity drops as voltage rises: 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.8 kA at 690 V. At 690 V the figure is low enough that you need to check whether it still coordinates with downstream devices — that's a selectivity study point, not a worry for standard 400/415 V distribution.
Mounting and environment
Dimensions are 105 mm wide, 181 mm high, 86 mm deep — a standard SENTRON 3VA frame size that fits Siemens panelboards and most DIN-rail enclosures with the appropriate adapter. IP40 on the front means it's protected against tools and solid objects larger than 1 mm, but not against water ingress; keep it inside a cabinet. Rated insulation voltage Ui is 800 V, and the operating temperature range is -25 °C to 70 °C. Storage range is wider: -40 °C to 80 °C. The 25 A rating holds flat across the entire operating temperature range — no derating needed up to 70 °C.