The clause that addresses direct measurement with fiber-optic detectors is expanded and an annex detailing examples of installation techniques for fiber-optic probes is added in this amendment.

Produce a guide for developing mathematical models and test procedures to determine the steady state maximum (hottest spot) and average winding temperature rise over ambient for liquid immersed distribution, power, network, and regulating transformers manufactured in accordance with IEEE C57.12.00.

This guide provides a basis for the transformer manufacturer and user to concur that a transformer meets the temperature requirements in C57.12.00. Those requirements state that the maximum winding temperature rise shall be determined by either direct measurement or calculations. This guide describes the requirements for a manufacturer's test program or mathematical model to demonstrate compliance with those requirements.