Its interrupting capacity hits 242 kA at 240 V and 187 kA at 415 V and 440 V — numbers that tell you this breaker clears high-fault scenarios without cascading upstream, which matters when you're coordinating a main or feeder in a plant with large transformer banks or multiple motor starters in parallel. Mounting is the standard SENTRON 3VA footprint — 105 mm wide, 181 mm tall, 86 mm deep — which drops into existing 3VA panel cutouts and bus-bar arrangements without re-drilling. The operating temperature range is -25 °C to 70 °C, storage from -40 °C to 80 °C, and maximum power dissipation is 10 W at rated load.
Thermal derating — the real continuous current at your ambient
Above that, it derates linearly: 96.25 A at 55 °C, 92.5 A at 60 °C, 88.75 A at 65 °C, and 85 A at 70 °C. The ETU350's long-time pickup can be adjusted down to match, but the breaker's thermal limits are what they are.
What the interrupting ratings mean for your system
At 240 V, the breaker clears 242 kA symmetrical — that's a very high interrupting rating, typical for a main breaker on a large low-voltage transformer secondary. At 500 V, it drops to 121 kA, and at 690 V, it's 5 kA — the 690 V figure is low enough that you'd need to verify the available fault current at that voltage level, but 690 V three-phase distribution is less common in standard IEC panels. The key takeaway: at the common 400/415 V level, this breaker handles virtually any fault a plant can throw at it.