What it is and what it does
The Siemens 3VA1225-5GF42-0BH0 is a SENTRON molded case circuit breaker (MCCB) designed for line protection — the primary role is to protect cables and busbars against overload and short-circuit in distribution panels. It carries a fixed 250 A rating across all four poles, so there's no adjustment range; what you order is what you get for the continuous current. Breaking capacity is the headline here: 187 kA at 240 V AC, 121 kA at 415 V, 75.6 kA at 440 V, 30 kA at 500 V, and 17 kA at 690 V. That 187 kA at 240 V means it can safely clear a fault of that magnitude without rupturing — important for high-fault locations like transformer secondaries or large motor control centers where available fault current is high. Thermal derating is published across the full operating range: full 250 A up to 50 °C, then 243 A at 55 °C, 237 A at 60 °C, 230 A at 65 °C, and 223 A at 70 °C. If your panel ambient runs hot — say a non-air-conditioned plant floor in summer — you need to account for the drop at 60 °C or above. Rated insulation voltage is 800 V, and the operating temperature range is -25 °C to 70 °C, with storage from -40 °C to 80 °C. The 800 V insulation rating means it's suitable for 690 V systems with margin.
Physical fit and integration
Dimensions: 70 mm deep, 140 mm wide, 158 mm tall. That 70 mm depth is shallow enough to fit most standard distribution enclosures without hitting the back wall — a common clearance issue with deeper MCCBs. Width of 140 mm for a 4-pole unit is typical for the frame size; check your DIN-rail or mounting-plate spacing before committing the panel layout. The breaker ships with an undervoltage release (UVR) and a 2-auxiliary-switch + 1 trip-alarm-switch HQ configuration. That means you get two form-C aux contacts for status feedback plus a dedicated trip alarm contact — enough for a basic motor control center or transfer scheme without adding an external accessory module. Maximum power loss is 59.5 W at rated current. That's heat that stays inside the enclosure; factor it into your thermal budget if the panel is tightly packed.
Lifecycle and sourcing posture
Lifecycle stage is current — Siemens actively manufactures and supports this order code. No phase-out notice or last-time-buy window is indicated.