Line protection with ETU350 — what the ratings mean for your panel
The Siemens SENTRON 3VA2163-6HN36-0BH0 is a 3-pole molded case circuit breaker (MCCB) rated for line protection, carrying a continuous current Iu of 63 A. The ETU350 electronic trip unit gives you adjustable overload and short-circuit protection curves — no communication module, no phase-failure detection, just a clean thermal-magnetic replacement for distribution panels that need selectivity headroom. The 242 kA breaking capacity at 240 V (187 kA at 415 V) means this breaker can interrupt very high fault currents without upstream fuses or a larger-frame device; for a 63 A MCCB that is an unusually high interrupt rating, so it fits close to the transformer secondary or in a high-capacity switchboard. The breaker includes an undervoltage release (UVR) as the auxiliary release — if the control voltage drops, the breaker trips, which is standard for emergency-stop or undervoltage protection schemes. The auxiliary contact block provides 2 auxiliary switches plus 1 trip alarm switch (HQ configuration), so you get separate NO/NC status feedback and a dedicated alarm contact that closes only on a fault trip.
Thermal derating and mounting — what changes above 55 °C
At 40 °C, 45 °C, and 50 °C the breaker holds the full 63 A without derating. At 55 °C it drops to 60.6 A, at 60 °C to 58.3 A, at 65 °C to 55.9 A, and at 70 °C to 53.6 A. If your panel ambient runs above 50 °C, size the load circuit accordingly — the ETU350 will track the temperature curve automatically. The 86 mm depth and 105 mm width fit standard SENTRON 3VA mounting footprints; the 181 mm height leaves clearance for the undervoltage release and auxiliary wiring at the top. Power loss is 6.5 W maximum — negligible for ventilation planning in a typical distribution board, but worth noting if you pack multiple breakers in a sealed enclosure.
Lifecycle and sourcing — current production, quoted to order
The lifecycle stage is marked current — this is an active, in-production part from Siemens. No phase-out or last-time-buy horizon is announced. For BOM-freeze or PCN-watch purposes, the 3VA2163-6HN36-0BH0 is available through independent distribution; pricing and lead time are confirmed at quote time against an RFQ.