This document summarizes a seminar presentation on underground cables. It discusses the construction of underground cables, including their core conductors, insulation, sheathing, bedding, armour, and serving. It also classifies cables based on voltage into low, high, super, and extra high tension cables. The key insulating materials discussed are rubber, XLPE, vulcanized rubber, impregnated paper, varnished cambric, and PVC. Examples of cable types include 3-core belted, 3-core, and 3-core SL type cables. Underground cables provide advantages like better appearance, protection from external disturbances, and lower maintenance costs, but their installation costs are higher than overhead systems.