What this MCCB is and what it does
The Siemens 3VA2125-7KP36-0AA0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection. It carries a continuous current rating of 25 A across its full ambient temperature range from -25 °C to 70 °C, with no derating needed up to 70 °C. The 3-pole construction and ETU850 electronic trip unit give it adjustable overload and short-circuit protection curves, plus an onboard communication function for integration into a monitored distribution system.
Breaking capacity — what the voltage-dependent ratings mean for your panel
This MCCB delivers 330 kA at 240 V, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3.7 kA at 690 V. The steep drop above 500 V is characteristic of a current-limiting design optimized for the 240–500 V range common in industrial distribution. For a 480 V panel, the 187 kA interrupting rating gives substantial headroom above typical available fault currents, so selectivity with downstream breakers is achievable without oversizing the upstream device. The 800 V rated insulation voltage confirms it is suitable for 690 V line-to-line systems where the breaker is used as a main disconnect.
Panel fit and environmental limits
Dimensions are 105 mm wide, 181 mm high, and 86 mm deep — a standard 3-pole MCCB footprint that fits most Siemens SENTRON mounting bases and panel cutouts. The front face carries an IP40 protection rating, meaning tools and fingers are kept out, but the breaker is not sealed against washdown; it belongs in a dry enclosure. Operating temperature spans -25 °C to 70 °C, with storage from -40 °C to 80 °C. Maximum power dissipation is 0.6 W, negligible for thermal budgeting inside a crowded panel.