The 63 A frame sits in the NSXm family, so it shares the compact 81 mm wide, 137 mm tall footprint and backplate mounting with the rest of the range.
For a 400 V distribution board with a transformer rating that pushes prospective short-circuit current into the 50–65 kA range, the H performance level gives headroom. Termination uses Everlink lugs: 2.5–95 mm² rigid or stranded aluminium/copper, or 2.5–70 mm² flexible copper. That covers everything from a 16 mm² branch feeder up to a 70 mm² main riser in one lug. The 9-module pitch (9 x 9 mm = 81 mm width) is standard for DIN-rail enclosures, though the breaker mounts to a backplate, not the rail itself. IK07 impact resistance handles accidental tool strikes during commissioning.
Electrical durability is rated 20,000 cycles at 440 V In/2 and 10,000 cycles at 440 V In; mechanical durability is 20,000 cycles. That is typical for a distribution MCCB — not a switching duty cycle, but adequate for infrequent manual switching and fault clearing. The breaker is certified for isolation per IEC 60947-2 (a visible gap when open), so it doubles as a disconnect without a separate switch. Power dissipation is 5.7 W per pole at rated current — about 17 W total for the 3-pole unit. That matters for enclosure thermal rise calculations when several breakers are ganged in a small panel.