MCCB for High-Fault Line Protection
The Siemens SENTRON 3VA2225-7HN32-0AD0 is a 3-pole molded case circuit breaker (MCCB) rated for 250 A continuous current at 40 °C, designed specifically for line protection in distribution panels. Its interrupting capacity reaches 330 kA at 240 V and 242 kA at 415 V, meaning it can safely clear faults up to those levels without upstream cascade failure — a critical parameter for high-fault installations like transformer secondaries or large motor control centers.
Current Rating and Thermal Derating
The breaker holds its full 250 A rating up to 50 °C ambient. Above that, derating is linear: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. For panel builders, this means the 250 A frame can serve a 250 A load only if the enclosure ambient stays at or below 50 °C; above that, the load must be reduced per the derating curve. Maximum power loss is 48 W.
Interrupting Capacity Across Voltages
SCCR values by system voltage: 330 kA at 240 V, 242 kA at 415 V, 242 kA at 440 V, 187 kA at 500 V, and 4.5 kA at 690 V. The steep drop at 690 V (4.5 kA) is typical for this class — the breaker is optimized for 240–500 V networks. For a 690 V installation, verify the available fault current does not exceed 4.5 kA, or select a higher-rated frame.
Physical Dimensions and Panel Fit
Dimensions: 181 mm height, 105 mm width, 86 mm depth. The 105 mm width (approximately 4.13 inches) is a standard 3-pole MCCB footprint for this current class. The 86 mm depth (3.39 inches) leaves clearance for rear-connected bus bars or cable lugs. No trip indicator, no voltage trigger, no undervoltage release, and no ground-fault monitoring are fitted on this variant — it is a basic line-protection breaker with 3 auxiliary switches (HQ type).