Siemens SENTRON 3VA1125-4EF46-0AA0 — 25 A, 4-Pole MCCB for Line Protection
The Siemens SENTRON 3VA1125-4EF46-0AA0 is a 4-pole molded case circuit breaker (MCCB) rated for 25 A at 40 °C, designed specifically for line protection in distribution panels. Its TM240 thermal-magnetic overcurrent release provides fixed thermal and magnetic trip settings, making it a straightforward choice for protecting cable runs and busbars against overloads and short circuits. The interrupting rating of 121 kA at 240 V gives substantial fault-current headroom for high-capacity downstream networks. With a width of 101.6 mm (4 in), height of 130 mm (5.12 in), and depth of 70 mm (2.76 in), this MCCB fits standard Siemens SENTRON panel footprints. The IP40 protection on the front face suits indoor switchboard mounting where tools-only access is acceptable. The 4-pole configuration handles three-phase-plus-neutral systems common in European and Asian distribution architectures.
Interrupting Capacity — What the Ratings Mean
The interrupting capacity drops with system voltage: 121 kA at 240 V, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. For a site engineer coordinating selectivity, the 75.6 kA at 415 V is the figure that governs most European industrial panels. The 11.9 kA at 690 V is the limiting case — if your transformer can deliver more fault current at that voltage, this breaker will not clear it safely, and you need a higher-rated frame. Temperature derating is mild: the 25 A rating holds steady from 40 °C through 50 °C, then drops to 24 A at 55–60 °C and 23 A at 65–70 °C. In a crowded panel with ambient above 50 °C, plan for a 1–2 A reduction per pole rather than a full frame upsizing.