Interrupting capacity and thermal derating — the numbers that govern the fit
The 3VA2063-5HN32-0KA0 is a Siemens SENTRON molded case circuit breaker (MCCB) carrying a 63 A rated continuous current (Iu) at 40 °C through 50 °C ambient. Per the datasheet, the interrupting capacity at 240 V is 187 kA, at 415 V and 440 V it holds 121 kA, at 500 V it drops to 79 kA, and at 690 V it is 3.4 kA. That 187 kA figure at 240 V is the headline — it tells you this breaker is sized for high-fault locations like transformer secondaries or large motor control centers where available fault current exceeds 100 kA. The ETU350 electronic trip unit provides adjustable long-time, short-time, and instantaneous protection curves, which is what you need for selective coordination downstream. Above 50 °C the breaker derates linearly: 60.6375 A at 55 °C, 58.275 A at 60 °C, 55.9125 A at 65 °C, and 53.55 A at 70 °C. If the panel ambient runs at 60 °C, the continuous load must stay under 58.275 A — the 63 A nameplate applies only up to 50 °C. The rated insulation voltage (Ui) is 800 V, so the breaker is rated for 690 V systems without derating the insulation path.
Physical fit and panel integration
The breaker measures 105 mm wide, 181 mm high, and 86 mm deep. That 105 mm width is the standard 3-pole MCCB footprint for this SENTRON frame size — it occupies three 35 mm DIN-rail modules plus a small margin. The 86 mm depth means it clears most 200 mm deep enclosures with room for rear busbar connections. No auxiliary contact is fitted as standard; the shunt trip (STL) is the only integrated auxiliary release. The basic switch variant is 3VA2063-5HN32-0AA0, and the integrated auxiliary trip is 3VA9688-0BL33.