Applies to unused oil delivered in tank wagons or in drums, intended for the immersion filling of transformers, switchgear and certain other electrical equipment in which oil is required as an insulant or for heat transfer. It specifies composition, appearance, characteristics, and method of sampling of the oil, and methods of testing for sludge and acidity after oxidation, flashpoint, viscosity, pour point, electric strength, acidity, corrosive sulphur, water content, density, loss tangent and resistivity.