... relationship and etc., it is especially used to check the cable connection conditions of the energy metering system ... and measured parameters in the screen, and easy to be operated;Real time measure three phase voltage, ... low current 1.5mA, it is suitable to check the cable connection status when no load, high precision, ... or lag, and find the 1008 types of cable connection mistakes of the 3p3w and 3p4w, ...