Revision Standard - Inactive - Superseded.This IEEE Standards product is part of the C57 family on Power Distribution and Regulating Transformers. Abstract: Recommendations regarding oil tests and evaluation procedures are made in this guide;references are made to methods of reconditioning and reclaiming conventional petroleum (mineral) dielectric insulating oils;the levels at which these methods become necessary; and the routines for restoring oxidation resistance, where required, by the addition of oxidation inhibitors. The intent is to assist the power equipment operator in evaluating the serviceability of oil received in equipment, oil as received from the supplier for lling new equipment at the installation site, and oil as processed into such equipment; and to assist the operator in maintaining oil in serviceable condition. The mineral oil covered is used in transformers, reactors, circuit breakers, load tap changers, and voltage regulators. Keywords :insulation testing , load tap changers , oil circuit breakers , oil insulation , power distribution maintenance , power transformer insulation , reactors , transformers , voltage regulators , IEEE C57.106