The K-curve trips between 10× and 14× rated current, designed for motor and inductive loads where a short inrush must not nuisance-trip a standard B or C curve. At 63 A on a single pole, this covers branch circuits feeding smaller motors, transformers, or welding equipment up to that continuous rating.
Panel integration
The 1-pole width (1 module at 18 mm) fits standard distribution boards and sub-distribution panels. At 63 A, terminal capacity and thermal dissipation in a closed enclosure should be checked against the manufacturer's derating tables — the 15 kA breaking capacity is rated at the declared voltage and assumes proper back-up protection from an upstream device if the prospective fault current exceeds that level.