At 0.3 A, this is a low-current branch or control-circuit protector, not a main feeder. That's a high-interrupting rating for a 0.3 A frame — it's sized for installations with high available fault current, typically industrial switchboards with large transformers nearby. At DC per IEC 60947-2 it's rated 15 kA, and under UL 1077 / CSA C22.2 No.235 it's 5 kA — so the part carries dual AC/DC ratings but the UL/CSA figure is lower. If the panel requires UL listing, the 5 kA SCCR governs. Current derating is published: 0.3 A at 45 °C, 0.29 A at 50 °C, 0.28 A at 55 °C. In a warm cabinet above 45 °C, the actual continuous current must be reduced accordingly — the 0.3 A label is only valid at the reference temperature.
Deployment context
Mounting position any, installation depth 70 mm. Combined terminal top and bottom — line and load can enter from either side, which simplifies panel wiring when busbars are pre-routed. Neutral conductor switching is built in (3P+N), so the neutral pole opens and closes with the phases. This is required in some national wiring rules (e.g., for TN-S systems) and avoids a floating neutral when the breaker is off.