This document specifies on-site infrared detection requirements, detection and diagnosis methods for internal overheating of gas-insulated metal-enclosed switchgear. This document is applicable to on-site infrared detection of internal overheating in SF6 gas-insulated metal-enclosed switchgear (GIS) with rated voltages of 72.5kV ~ 252kV. On-site infrared detection of internal overheating of SF6 gas insulated metal enclosed transmission lines (GIL) can be used as a reference.