63 A MCCB with ETU350 — what the ratings mean for your panel
The Siemens SENTRON 3VA2163-5HN36-0BL0 is a 3-pole molded case circuit breaker rated for 63 A continuous current at 40 °C, with no derating needed up to 50 °C — the full 63 A holds across that range, then steps down to 60.6 A at 55 °C and 53.6 A at 70 °C. That thermal curve matters when you're packing breakers into a warm enclosure: you lose only about 15 % of the rating at the top of the operating band. The ETU350 electronic trip unit gives you adjustable overload and short-circuit protection curves, not a fixed thermal-magnetic bimetal. That means you can coordinate selectivity downstream without swapping hardware — set the I²t on/off and the short-time pickup to match your feeder breaker. The 800 V rated insulation voltage (Ui) confirms it's built for 690 V line-to-line systems with margin.
Breaking capacity — where it interrupts and where it doesn't
Rated short-circuit breaking capacity (Icu) runs 187 kA at 240 V, 121 kA at 415/440 V, 79 kA at 500 V, and 4.25 kA at 690 V. The steep drop at 690 V tells you this breaker is sized for 400–500 V distribution — at 690 V it still clears a fault, but the 4.25 kA limit means you need a higher-rated frame if your available fault current exceeds that.
Auxiliaries and releases — what's inside the accessory slot
Factory-fitted with an undervoltage release (UVR) that drops the breaker on loss of control voltage — standard for safety circuits where you need guaranteed disconnect on power failure. The auxiliary contact block carries 2 auxiliary switches + 1 trip alarm + 1 electrical alarm switch (HQ type), enough to signal position and trip status back to a PLC without an extra interposing relay. The integrated undervoltage release is order code 3VA9608-0BB11; the basic switch module is 3VA2163-5HN36-0AA0. Both are replaceable in the field if the coil or contacts fail, though the UVR coil rating needs to match your control supply.
Mounting and panel fit
Dimensions: 105 mm wide × 181 mm high × 86 mm deep. The 105 mm width is standard for a 3-pole 3VA2 frame — it occupies three 35 mm DIN modules plus a sliver for the arc chamber. Depth of 86 mm leaves room behind a 200 mm deep enclosure for wiring and the UVR coil.