The Siemens SENTRON 3VA1225-4EF42-0AE0 is a 4-pole molded case circuit breaker (MCCB) rated for 250 A continuous at 40 °C, designed for line protection in distribution panels and motor control centers. Its TM240 thermal-magnetic release provides overload and short-circuit protection without electronic adjustment — a fixed-trip design that eliminates configuration errors during commissioning. Breaking capacity is 121 kA at 240 V and 75.6 kA at 415 V, giving the breaker headroom for high-fault installations like main feeders or transformer secondaries where SCCR must coordinate with upstream gear. At 690 V it still interrupts 11.9 kA, so it holds up on 600 V class systems as well. The 70 mm depth, 140 mm width, and 158 mm height fit the standard SENTRON 3VA footprint — direct swap into existing Siemens MCCB panel layouts without re-drilling gland plates or reworking bus connections. Max power loss is 57 W, which matters for thermal rise inside a sealed enclosure.
Current derating and ambient limits
The 250 A rating holds flat from 40 °C through 50 °C. Above that, derating is gradual: 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If the panel ambient runs above 50 °C, size the breaker at the derated value — don't assume the nameplate 250 A holds at the top of the operating range. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. The storage limit governs handling during transport and warehouse dwell — the breaker can sit in a cold stockroom but must be at operating temperature before being loaded.
Auxiliary switching and accessories
This variant ships with four HQ auxiliary switches (design of the auxiliary switch: 4 auxiliary switches HQ). No undervoltage release, no ground-fault monitoring, no communication function — it's a pure line-protection breaker. The supplied basic switch order code is 3VA12254EF420AA0, which is the core MCCB module before auxiliary additions. Insulation voltage is rated at 800 V, so the breaker is suitable for 690 V systems with margin. No trip indicator or voltage trigger is fitted.