63 A MCCB with ETU350 — what the ratings mean for your panel
The Siemens 3VA2163-6HN36-0AE0 is a 3-pole SENTRON molded case circuit breaker rated for 63 A continuous current (Iu) and fitted with an ETU350 electronic trip unit. This is the line-protection version — no undervoltage release, no voltage trigger, no communication module — built for straightforward overcurrent protection in a distribution panel. The 63 A rating holds flat from 40 °C up to 50 °C ambient; above that it derates to 60.6 A at 55 °C and 53.6 A at 70 °C, so if your enclosure runs hot, size the breaker for the actual ambient, not the nameplate. Interrupting capacity is the headline number here: 242 kA at 240 V AC, 187 kA at 415/440 V, 121 kA at 500 V, and 5 kA at 690 V. That 242 kA figure at 240 V is unusually high for a 63 A frame — it means this breaker can sit upstream of a high-fault transformer or a large motor bank without needing a current-limiting fuse ahead of it. At 690 V the rating drops to 5 kA, so if you're on a 690 V line, verify the available fault current at the point of installation. The ETU350 is a basic electronic trip unit — no ground-fault monitoring, no phase-failure detection, no communication. It handles LSI protection (long-time, short-time, instantaneous) with adjustable pickup and delay settings via DIP switches on the front face. The 4 auxiliary switches (HQ version) give you status feedback for remote monitoring or PLC inputs. Front IP40 protection keeps dust out of the enclosure face; the breaker itself is designed for panel-mount, not washdown environments.
Panel fit and dimensions
Dimensions are 105 mm wide, 181 mm high, 86 mm deep — a standard 3-pole MCCB footprint for the SENTRON 3VA2 frame. Mounts on a DIN rail or directly to a backplate via screw terminals. The 86 mm depth leaves room for rear-panel wiring in a 200 mm deep enclosure. Terminal layout accepts copper or aluminum conductors up to the rated cross-section; the 4 auxiliary switches add about 18 mm to the width compared to a bare breaker.
Thermal and environmental limits
Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. Maximum power loss is 4 W at rated current — negligible for panel cooling calculations. The latching endurance is rated at 20,000 operations, which is typical for a distribution breaker not used for frequent switching. If you're cycling this breaker daily as a disconnect, that's fine; if you're switching it hourly, consider a contactor upstream.