63 A MCCB with ETU320 — what the ratings mean for your panel
The Siemens 3VA2163-6HL36-0AF0 is a 3-pole SENTRON molded case circuit breaker rated for 63 A continuous current (Iu) across ambient temperatures from 40 °C to 50 °C without derating — at 55 °C it still carries 60.6 A, at 70 °C it's 53.6 A. That thermal stability means the breaker holds its rating through most panel internal temperature rises without forced derating. Interrupting capacity is 242 kA at 240 V, 187 kA at 415/440 V, 121 kA at 500 V, and 5 kA at 690 V — numbers that put this squarely in high-fault-current distribution, not branch-only protection. The ETU320 electronic trip unit gives adjustable long-time, short-time, instantaneous, and ground-fault protection curves, which is the difference between nuisance tripping and selective coordination downstream. This is a line-protection version (not motor-protection), so it's sized for feeder and main breaker duty in distribution panels, switchboards, or as a transformer secondary protector. The IP40 front protection suits enclosed panel mounting — not outdoor or washdown.
Physical fit and panel integration
Dimensions: 105 mm wide, 181 mm high, 86 mm deep. The 86 mm depth is the key dimension for enclosure depth clearance — it fits standard 200 mm deep distribution boards with room for wiring gutters. Width of 105 mm is the standard 3-pole MCCB footprint; it mounts via the SENTRON panel-mounting foot or DIN rail adapter (not included).
Auxiliary contacts and trip signaling
Comes with 1 auxiliary switch + 1 trip alarm switch (HQ version). The trip alarm signals when the breaker trips on fault — distinct from the aux switch which follows handle position. This matters for remote fault annunciation in UPS or generator feeder circuits where you need to distinguish a manual open from a trip event.