Nonlinear, like capt al my job also affords me the opertunity to use a high end FLIR P-60 IR camera. I mostly use it to inspect high voltage electrical switch gear, transformers, pump motors, 480vac starters, lighting panels, etc. Works very well. But I have been challanged by other crafts based on there findings with an IR thermometer. yes you can get accurate temp at 30' with the IR camera, but several factors need to be worked into your figure. Such as wind speed, humidity, imissivity, etc. Your IR thermometer can give you some close readings but one very important word of caustion to remember when using your IR thermometer is that it averages the S.S.R. (spot size ratio). Very simply put if your S.S.R. is 250 to 1 you can be 250' away from a 1' target. But here is the tricky part, your 1' target, say it's a junction box with a 3-phase motor termination and on phase is hotter then the other two. The IR thermometer will average everything within that 1' area. So @ 30' your probaly wasting $200.00 bucks. Within the 3' to 5' range, yea it's a neat tool to have for referancing hot breakers in a lighting panel.
