The 250 A rating holds across ambient temperatures from 40 °C to 50 °C without derating; above 50 °C the continuous current steps down to 241 A at 55 °C and 213 A at 70 °C, so a panel builder working a warm enclosure should check the thermal curve before locking in the wire size. Interrupting capacity reaches 121 kA at 240 V, 75.6 kA at 415 V, and 52.5 kA at 500 V — figures that cover most North American and European low-voltage fault levels. The part carries IP40 on the front face — splash-protected in the panel but not rated for washdown zones.
Mounting is via the rear panel or DIN rail adapter plate (not included). Verify the busbar or lug kit separately — the breaker ships without terminals. The ETU320 trip unit draws its power from the line-side current, no auxiliary supply needed.