63 A, 187 kA — the interrupting curve that decides fit
The Siemens 3VA2163-5JP32-0DC0 is a SENTRON molded case circuit breaker (MCCB) rated for 63 A continuous current at 40 °C, with an interrupting capacity of 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 4.25 kA at 690 V. That 187 kA figure at 240 V is the headline — it tells you this breaker is sized for high-fault panels where the available short-circuit current is well above what a standard 25 kA or 65 kA MCCB can handle. The 4.25 kA at 690 V is the other end of the curve; if your system runs at 690 V, the fault current at the breaker must stay under that limit or you need a higher-rated frame. The ETU550 electronic trip unit handles the protection curve. It is a line-protection version — no ground-fault monitoring, no phase-failure detection, no voltage trigger. What it does have is a communication function and an undervoltage release (UVR) as the auxiliary release, plus two auxiliary switches (HQ type) for status feedback to a PLC or annunciator panel.
Thermal derating — the real-world current limit
The 63 A rating holds at 40 °C, 45 °C, and 50 °C. Above that, the breaker derates: 60.6 A at 55 °C, 58.3 A at 60 °C, 55.9 A at 65 °C, and 53.6 A at 70 °C. If this breaker lives in a non-air-conditioned enclosure next to a drive or transformer, use the 55 °C or 60 °C column for your load calculation — not the 40 °C number. The maximum operating temperature is 70 °C; storage range is -40 °C to 80 °C. Physical footprint: 105 mm wide, 181 mm high, 86 mm deep. That 105 mm width is three-pole wide on a standard DIN-rail or panel-mount footprint. The 86 mm depth means it clears most 200 mm deep enclosures with room for wiring gutters. Power loss at rated current is 6.5 W maximum — negligible for thermal budgeting in a ventilated panel, but worth noting if the enclosure is sealed and densely packed.