It was diagnosed customer transformers and other equipment by using non-contact infrared equipment. Examiners can identify not only abnormalities in real time in the field of the transformer immediately, as well as they were able to safely perform the scan. Thanks to successful transformer diagnosis, we can easily diagnose abnormalities of transformer itself which can be caused by deterioration of the oil used as overlaod or refrigerant and we can also diagnose abnomalities from low voltage bushing which can be result by external environmental factors and physical factors and abnomalities from its connections at the same time we found it is very useful at proactive diagnostics.