The Siemens 3VA1125-3EF32-0JA0 is a 3-pole SENTRON molded case circuit breaker (MCCB) rated for 25 A continuous current (Iu) with a TM240 thermal-magnetic overcurrent release. It carries a 75.6 kA interrupting capacity at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and 10.5 kA at 690 V — figures that govern its fault-clearing ability at the panel's service voltage. The part is configured for line protection only (no ground-fault monitoring, no communication function, no auxiliary contacts) and includes a shunt trip (STL) auxiliary release (order code 3VA9688-0BL32) for remote tripping.
What the interrupting ratings mean for fit
The 75.6 kA at 240 V rating is the highest short-circuit current this MCCB can safely interrupt at that voltage — relevant for 240 V delta or split-phase services. At 415 V (common in European industrial panels) the rating drops to 52.5 kA, and at 690 V it falls to 10.5 kA. These are the values a panel designer checks against the available fault current at the breaker's mounting point; if the service's prospective short-circuit current exceeds the rating at the operating voltage, the breaker may not clear the fault without damage.
Thermal derating and continuous current
The 25 A rated continuous current (Iu) holds flat from 40 °C to 50 °C ambient. Above 50 °C it begins to derate: 24 A at 55 °C, 23.5 A at 60 °C, 23 A at 65 °C, and 22.5 A at 70 °C. For a panel that runs warm — say, a packed enclosure near a furnace line or in a hot climate — the actual load must be kept below the derated figure at the enclosure's internal ambient. The TM240 release is a fixed thermal-magnetic type; no interchangeable trip unit, so the breaker's continuous rating is set at the factory.
Panel fit and dimensions
The MCCB measures 130 mm high, 76.2 mm wide, and 70 mm deep. The 76.2 mm width (3 inches) is the standard footprint for a 3-pole SENTRON 3VA1 frame; it mounts via screw-clamp lugs to a backplate or DIN-rail adapter (not included). The 70 mm depth leaves clearance for rear-connected busbars or cable ducts behind the breaker. IP40 on the front means the breaker face is protected against tools and small wires but not against water ingress — standard for dry indoor panel mounting.