I have a customer that I wire his refrigerated storage building, the one I asked about on a different post, ( and by the way, it went good, inspection went fine the first time [Linked Image] But anyway he asked me to check into what it would take to wire "hour meters" on his two outdoor compressors, just to see how hard each compressor was working, in other words, to make sure one compressor wasn't doing all the work, and the other one doing nothing. There both controlled by a separate thermostat inside the freezer, but the freezer is only 40ft. long and 12ft. wide so he's thinking that maybe only one may do the job, especially in the cooler months. Anyone ever had any experience on this and know of some knowledgable sites that might point me in the right direction on prices etc.? It seems pretty simple, just run the feed to the time clock on the hour meter from each compressor. By the way, each compressor is 3 phase... Thanks for the input. Steve...