A Criterion of Quality of Cable Insulation

Radial uniformity of oil impregnated paper cable insulation, that is, uniformity in a radial direction from conductor to sheath, is a characteristic of well manufactured cable that is fully as important or more so than longitudinal uniformity. Radial power factor curves for several brands of new cable included in this paper show marked irregularities which are attributed to poorly controlled manufacturing methods. On the basis of such studies, some manufacturers have made efforts to improve the radial uniformity of their insulation with resulting great improvement in quality. This characteristic of cable insulation thus provides a criterion of insulation quality that should be useful to both manufacturer and user.