An insulating fluid for impregnating the solid insulation of an oil-filled electric power cable, particularly for a cable to be submerged in water, which comprises at least one lower aliphatic derivative of napthalene, preferably, 1 methylnapthalene or 1, 2, 3, 4-tetrahydronapthalene, or mixtures thereof or a mixture of one or more lower aliphatic derivatives of naphthalene with a conventional impregnating fluid. In the latter case, the derivative is present in a significant amount and preferably, is present in an amount sufficient to provide a specific gravity substantially equal to the specific gravity of water. Also, an electric power cable having its insulation impregnated with such insulating fluid.
展开▼