Quick answer
For a single-core 1100 V XLPE copper cable to IS 7098 Part 1: about 260 A laid direct in the ground at 30°C, and 303 A in air at 40°C. Those figures assume standard conditions — deeper laying, hotter ground or grouped cables all reduce them, which is what derating factors are for. The full table from 4 to 1000 sq mm, with aluminium equivalents, is on our current-rating chart.