Line-down spare: what fits, what doesn't
The Siemens 3VA1163-3EF32-0AG0 is a SENTRON molded case circuit breaker (MCCB) spec'd for line protection — 3-pole, 63 A continuous at 40 °C, with a TM240 thermal-magnetic release. That TM240 means the thermal pickup is fixed at 63 A; the magnetic trip is adjustable between 5–10× In (315–630 A). It's current-production, so no last-time-buy scramble. Breaking capacity is the headline: 75.6 kA at 240 V, 52.5 kA at 415 V, 32 kA at 440 V, and it still holds 11.9 kA all the way up to 690 V. That's enough SCCR headroom for most 480 V distribution panels without needing a current-limiting fuse upstream — the IEC 60947-2 rating covers it. Rated insulation voltage is 800 V, so it's comfortable on 690 V systems. The auxiliary switch pack includes one auxiliary contact plus one trip-alarm switch — that's the standard HP configuration for signaling the breaker state back to a PLC or annunciator panel.
Thermal derating: the real-world current
The 63 A rating holds flat from 40 °C to 50 °C — no derating in that band. At 55 °C it drops to 62 A, at 60 °C to 61 A, at 65 °C to 60 A, and at 70 °C to 58 A. That's a shallow slope; if your panel ambient is 65 °C you still get 60 A, which is 95% of nameplate. The maximum power loss is 17.3 W, so enclosure heat rise is manageable with standard ventilation.
Panel fit and footprint
Dimensions: 130 mm high, 76.2 mm wide, 70 mm deep. That's a standard 3-pole MCCB footprint — bolts into a SENTRON mounting plate or direct-panel mount. The width is important for multi-breaker groupings: 76.2 mm per pole center matches the standard 25.4 mm pitch, so three poles occupy three module spaces on a DIN-rail adapter plate. Operating temperature range is -25 °C to 70 °C; storage range is -40 °C to 80 °C. If this lives in an unheated enclosure in a northern climate, the cold-start behavior is fine — the thermal-magnetic release isn't affected by low ambients the way electronic trips can be.