MCCB with ETU550 — interrupting capacity and thermal derating
Its interrupting capacity is 330 kA at 240 V and 242 kA at 415 V — these numbers cover high-fault scenarios at the service entrance or downstream of a large transformer, where available fault current can exceed 200 kA. The breaker carries three auxiliary switches (HQ) for remote status indication, plus an undervoltage release with leading NO contacts — the leading contact arrangement means the UVR signals its own state before the breaker opens, useful in safety circuits that need to confirm the release is reset before reclosure.
Thermal derating — what the 25 A rating actually means in a warm panel
At 55 °C it derates to 24.1 A, at 60 °C to 23.1 A, and at 70 °C to 21.25 A. Plan for the ambient inside the enclosure, not the control-room temperature.
Integration — dimensions, auxiliary components, and panel fit
These are the factory-matched accessories for this breaker variant — order them alongside if the panel build requires the UVR or auxiliary switch to be pre-installed.