What the ratings mean for fit
The 3VA1163-3EF36-0AA0 is a Siemens SENTRON molded case circuit breaker rated for 63 A continuous current with a TM240 thermal-magnetic overcurrent release — the 240 refers to the trip unit's frame rating, so this breaker is sized for a 63 A branch circuit but lives in a 240 A frame, giving mechanical headroom for high interrupting duty. At 240 V it breaks 75.6 kA; at 415 V, 52.5 kA; at 690 V, 11.9 kA. That curve tells you the breaker is built for low-voltage distribution where fault current is highest at the transformer secondary — 75.6 kA at 240 V is a serious interrupting rating for a 63 A device, meaning it can clear a bolted fault on a large step-down transformer without venting or welding contacts. Thermal derating is flat from 40 °C to 50 °C at 63 A, then drops to 62 A at 55 °C, 61 A at 60 °C, 60 A at 65 °C, and 58 A at 70 °C. If the breaker sits in a crowded panel with ambient above 50 °C, the continuous current capacity shrinks — a 60 °C enclosure means you lose 2 A off the nameplate rating. Plan the load accordingly. Rated insulation voltage is 800 V, so the breaker is suitable for 690 V line-to-line systems with margin. The -25 °C to +70 °C operating range and -40 °C to +80 °C storage range mean it survives the nacelle — no up-tower swaps for cold-soaked gear. Storage minimum of -40 °C handles winter transport without brittle fracture risk.
Panel fit and footprint
Three-pole design, 76.2 mm wide (3 inches), 130 mm tall (5.12 inches), 70 mm deep (2.76 inches). That width is a standard 3-module DIN-rail footprint — drops into a panel that was laid out for a 3-pole MCCB without re-drilling the gland plate. No undervoltage release, no communication module, no ground-fault monitoring — this is a bare line-protection breaker with a TM240 thermal-magnetic trip. If the BOM calls for shunt trip or aux contacts, those are external add-ons, not internal.