The 63 A rated operating current sets the maximum continuous load this RC unit can carry — sized for a main incoming supply or a large sub-feed in a distribution board. The 1000 mA residual trip threshold is deliberately high: this is not for personal shock protection (which requires 30 mA), but for equipment protection against earth leakage currents that could cause fire or insulation degradation. The selective design means it withstands 5 kA surge current without tripping, so it sits upstream of standard RCDs and lets downstream units clear first — critical for maintaining supply to healthy circuits during a fault. Type A fault current sensitivity covers AC residual currents and pulsating DC — the kind produced by single-phase rectifiers in switched-mode power supplies, variable-speed drives, and LED drivers. If your panel feeds electronics or motor drives, Type A is the minimum; a standard AC-type RCD may not detect pulsating DC and could fail to trip.
Snaps onto DIN rail (REG) and occupies 2 width units — 71 mm wide — in a standard distribution board. Depth is 70 mm, installation depth also 70 mm, so it sits flush with the MCB it pairs with.