Thermal cameras for inspecting installations

[TomVA (Tom Powers)]

If you are going to do thermal imaging. Two things to remember. (1) these cameras are generally set up for an impassivity of 0.95 which is great for cable jackets, paint on walls, and such. Metal has a much lower emissivity and will show up way cooler than they actually are. To get around this I always put strips of electrical tape on any metal surface that I care about as it has an emssivity of 0.95. Second when you want to see the heat source on heavy cables (e.g. 4/0) you need to take several images in succession right after you start a high current operation. Assuming that the attached image makes it. I shows the thermal transient on some 4/0 cable after turning on 175A of current flow. It shows that the heat seems to be supplied connection of the lug and not from the Class T fuse that is in the middle. Also there are little squares of electrical tape on the bolts and on the lug itself. In the lower image the light green in yellow is where the metal is peaking out between the heat shrink and the black electrical tape. The temperature on the metal is indicating about 10F lower than the lug actually is.