What this 800 A MCCB carries — and where the rating holds
The Siemens SENTRON 3VA2580-5KQ32-0KH0 is a 3-pole molded case circuit breaker rated for 800 A continuous current at 40 °C, with the same 800 A holding through 60 °C — only at 65 °C does it begin to derate to 767 A, and at 70 °C to 703 A. That flat thermal curve means this breaker delivers its full 800 A rating across most normal panel ambient conditions without headroom loss. Its interrupting ratings are tiered by system voltage: 187 kA at 240 V, 121 kA at 415 V, and 53 kA at 690 V. For a main breaker on a 415 V distribution board, the 121 kA SCCR gives substantial fault-clearing headroom — enough to coordinate with downstream feeders without cascading. The ETU860 electronic trip unit provides adjustable long-time pickup (Ir) up to 800 A, short-time delay (tsd) from 0.05 s to 0.5 s, and ground-fault summation sensing on the line conductors. Communication function is built in, so the breaker can report status and trip events to a higher-level control system.
Panel fit — dimensions and integration
The breaker measures 210 mm wide, 320 mm high, and 120 mm deep — a 3-pole frame that fits standard SENTRON mounting patterns. Front protection is IP40, suitable for enclosed panel mounting where the door or cover shields the breaker face from tool drops and dust. Maximum power loss is 135 W at rated current; factor that into enclosure thermal calculations if the panel is densely packed or operating near the 70 °C upper ambient limit.