What it is and what it does
The Siemens 3VA1225-5EE42-0AA0 is a SENTRON molded case circuit breaker (MCCB) built for line protection in distribution panels. It carries 250 A continuously at 40 °C without derating, and the thermal-magnetic TM220 release handles overload and short-circuit trip curves in one package. Four poles mean it switches all three phases plus the neutral, which matters for TN or TT systems where the neutral needs overcurrent protection.
Breaking capacity — what the voltage columns tell you
This MCCB interrupts 187 kA at 240 V, dropping to 121 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. That is a steep SCCR curve — the part is clearly designed for low-voltage high-fault applications (think transformer secondaries or large busway feeds) where available fault current is extreme. At 690 V the 17 kA rating still covers most industrial motor-control center main breakers. The 4-pole frame also handles DC switching per the 3VA device manual, though the AC ratings are the headline numbers here.
Thermal derating and panel integration
Rated 250 A from 40 °C through 50 °C, then it begins to taper: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, 223 A at 70 °C. If the breaker sits in a sealed enclosure with other heat sources, expect to size up one frame or ventilate. The 70 mm depth and 140 mm width fit a standard MCCB footprint — no oddball cutout. IP40 on the front face keeps dust out of the trip mechanism; the rest of the breaker is open to the panel interior, which is normal for switchgear.
Lifecycle and sourcing
The lifecycle stage is listed as current — meaning this is an active, in-production catalog number from Siemens. No PCN or phase-out notice is on record. For a BOM freeze or a panel design that needs a repeatable supply line, this is a safe pick. Available to quote against an RFQ through independent distribution; availability and current pricing confirmed at quote time.