Model 380385 utilizes polarization index measurement, which is a ratiometric test used to assess the performance of insulation. Insulation starts to age as soon as it is made, and as it ages, its insulating performance deteriorates. The insulation tester identifies this deterioration so corrective steps can be taken. Its test voltages range from 10 kV to 500 V at 500 V increments and insulation resistance reaches as high as 25 GΩ at 500 V and 500 GΩ at 10 kV.

Extech Instruments, (781) 890-7440