The D-curve trips between 10× and 20× rated current, so it holds through the magnetizing surge of a small motor or solenoid bank. The DC rating is 15 kA per the same standard, and UL 1077 / CSA C22.2 No. 235 lists it at 5 kA for North American recognition.
Mounting position is unrestricted — vertical, horizontal, or inverted. The combined terminal at top and bottom accepts conductors for loop-through wiring without extra bridging bars.
Temperature derating and ambient limits
Rated 4 A at 45 °C ambient. At 50 °C the continuous rating drops to 3.88 A; at 55 °C it is 3.75 A. The breaker is rated for ambient from -40 °C to 75 °C, with humidity limits of 95% RH up to 55 °C, 55% RH at 70 °C, and 35% RH at 75 °C. If the panel ambient exceeds 45 °C, size the load accordingly — the thermal-magnetic trip element responds to the actual conductor temperature, so a 4 A load at 55 °C may nuisance-trip or run at the edge of the thermal curve.