It is often said that first impressions count. When it comes to infrared inspections of electrical distribution systems, first impressions may be incomplete or misleading especially when an inspection is not properly performed.
The greatest amount of labor expended during an infrared inspection of electrical equipment is often associated with the opening/closing of electrical panels. In an effort to reduce labor costs, some have suggested scanning the exterior of electrical enclosures and opening only those that exhibit a discernible temperature rise. This approach is flawed in that it often overlooks significant thermal anomalies that can lead to catastrophic failures or unexpected downtime.
Depending upon the construction and condition of electrical equipment, significant thermal anomalies may be undetectable when panel covers remain closed. Such anomalies include, but are not limited to: loose/deteriorated connections, overloads, or arcing. Because infrared equipment cannot see through solid objects such as steel and phenolic, industry practice and published standards require that electrical enclosures be opened to afford a clear line-of-sight to subject components.
At present, there is no way to correlate enclosure temperatures to the integrity of the devices they contain. Thermographers who use enclosure temperatures as indicators of device integrity face two problems. First, they will miss significant deficiencies. Second, they may invite undue liability should a hidden problem cause a catastrophic failure or unexpected downtime.