For 3 phases circuits,balanced load 45-65Hz and for 1 phases AC 50Hz.Model:HH-96 HH-72Class:2.5 Voltage:100V,380V,400VFrequency:50Hz,60Hz Scale graduation:0.5 cap-1-0.5ind  0.3cap-0.7ind  0.4cap-1-0.4ind  0.7cap-1-0.3ind.Orders to be Noted:Type of current:1P, 3P, 3W circuits, balanced loadRated volt:The voltage is line voltage (between two wires)  Operating current:if used with CT,the secondary current 5A or 1A is standard