C-H, Voltage Drop, is not really taken that seriously over here. I normally only use the Data Logger, for Fault-finding purposes, where there is a serious drop in voltage, and further more, this really only occurs in Commercial/Industrial installations, I think that I have only used the DLogger, in a domestic situation once, by memory. It's just handy to see what is happening to the Voltage(especially 3phase), over a longer period of time.