... :-Instrument Transformer Tester, Model ITC-C,-Standard reference CT, Model HL-62CS-Current load box ... and the ratio mistake. Technical Specifications: Instrument Transformer Tester, Model ITC-C -Input: Power ... -Standard current ratio: ² Primary:5,7.5,10,15,20,25,30,40,50,60 ... -Temperature: 5°C ~ 40°C -Humidity: <80%(25°C) -Altitude :< 2500m High Accuracy Current Transformer Calibrating Tester/Testing