For the past ten years Ontario Hydro has used mobile infrared thermographic equipment as an integral part of its substation maintenance program. Because of the geographic size of the Province of Ontario, the frequency of inspection required, and the capital cost of the inspection equipment, each region carries out its own thermographic inspection using mobile equipment provided by Head Office. In order to provide a high level of diagnostics and information transfer, the latest generation of van has been outfitted with a thermal imager which is not gas or nitrogen cooled, a video camera, computer, printer and custom analysis software. Both the thermal and video images are digitized, redisplayed and analyzed by the computer, with only supervisory input from the operator. A report, complete with images, is automatically printed in the van and as well, a file is created which is sent to the Head Office for review, storage, and inclusion into a maintenance data-base. The use of automatic data collection and expert-system based software effectively leads the part-time operators through the complex operation of the equipment, radiometric quantification, and common interpretation of the thermal imagery.