630 A SENTRON MCCB with ETU850 — what the ratings mean for your panel
The Siemens 3VA2463-6KP32-0HH0 is a 3-pole SENTRON molded case circuit breaker rated for 630 A continuous current at 40 °C, with an ETU850 electronic trip unit. The 630 A figure is the maximum uninterrupted current the breaker can carry under the listed conditions — above that, the trip unit initiates a protective opening. The ETU850 provides adjustable long-time, short-time, instantaneous, and ground-fault protection curves, which means you can coordinate selectively with downstream breakers rather than relying on a fixed thermal-magnetic characteristic. Breaking capacity is the other headline: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 40 kA at 690 V. These are the maximum fault currents the breaker can safely interrupt at each voltage level without welding contacts or rupturing the arc chamber. For a 480 V panel, the 187 kA figure at 440 V is the relevant bound — verify your available fault current stays under that. The breaker includes a shunt trip release (STL) for remote tripping, two auxiliary switches plus one trip alarm switch (HQ configuration), and a communication function. The front panel carries IP40 protection.
Temperature derating — the curve that governs real-world current
The 630 A rating is valid at 40 °C ambient. Above that, the breaker must be derated: 600 A at 45 °C, 570 A at 50 °C, 540 A at 55 °C, 510 A at 60 °C, 480 A at 65 °C, and 450 A at 70 °C. If your panel ambient runs at 50 °C, the usable continuous current drops to 570 A — a 9.5 % reduction. The operating temperature range is -25 °C to +70 °C, with storage from -40 °C to +80 °C.
Dimensions and panel fit
Physical footprint: 248 mm height, 138 mm width, 110 mm depth. The 138 mm width is the 3-pole frame width — verify the mounting cutout in your switchgear matches. The 110 mm depth includes the rear arc chamber and terminal extensions; ensure clearance behind the mounting plate for cable lugs and bus connections.
Power loss and thermal management
Maximum power loss is 162 W at rated current. That heat must be dissipated inside the enclosure — factor it into your panel cooling calculation, especially if the breaker is grouped with other high-current devices in a sealed cabinet.