What this MCCB delivers in the nacelle
The Siemens 3VA1580-5EF32-0JA0 is a 3-pole SENTRON molded case circuit breaker rated 800 A continuous at 40 °C, with a TM240 thermal-magnetic overcurrent release and an integral shunt trip (STL) for remote tripping. Breaking capacity hits 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 52.5 kA at 690 V — numbers that matter when a turbine's converter bus or main feeder sees a stiff grid fault.
Thermal derating — the real-world current
Above that it steps down: 780 A at 55 °C, 761 A at 60 °C, 741 A at 65 °C, and 722 A at 70 °C (–). The 240 W maximum power loss also needs to be ventilated out of the enclosure; that's not trivial in a sealed offshore cabinet.
The breaker measures 210 mm wide, 320 mm high, and 120 mm deep. That 210 mm width is a standard 8.27-inch footprint for this class of SENTRON MCCB. The 120 mm depth (4.72 in) leaves reasonable gutter space behind the panel door for wiring and the shunt trip connections.
Key features at a glance
Line-protection design with no communication function, no undervoltage release, and no ground-fault monitoring. The shunt trip (STL) auxiliary release allows a remote trip signal — useful for emergency-stop chains or SCADA-driven isolation. The TM240 thermal-magnetic release gives fixed thermal and magnetic pickup settings.
The closest functional peer in the same SENTRON family is the 3VA1110-5EF32-0LA0. The critical difference is the continuous current rating: the 3VA1580 carries 800 A at 40 °C, while the 3VA1110 is a lower-frame model. Both share the 3-pole form, shunt trip, and similar breaking capacities at the same voltage points, but the 3VA1110 frame physically cannot deliver the 800 A continuous rating. If your BOM specifies 800 A, the 3VA1580-5EF32-0JA0 is the correct frame; the 3VA1110 will not drop in without a redesign.