New IEEE Standard - Superseded. This guide includes guidelines for following: insulating oil maintenance and diagnostics, oil reclamation, testing methods for the determination of remaining insulation (paper) life, and upgrades of auxiliary equipment such as bushings, gauges, deenergized tap changers (DETCs), on load tap changers (LTCs) (where applicable), and coil reclamping. The goal of this guide is to assist the user in extending the useful life of a transformer.