High-power electricity cables with transfers in the gigawatt range* have their own special characteristics which separate them from lower voltage distribution cables and domestic wiring. The larger size exacerbates features and problems such as mechanical handling and, particularly, heating effects. This article, based on the 36th Hunter Memorial Lecture, measures progress over the last quarter century since D.T. Hollingsworth gave the 11th Hunter Memorial Lecture(1) though he was speaking of all types of underground cable whereas the present scope is narrower.