Class 1 Transformer
Insulation resistance tests between each winding and earth
Insulation resistance test between windings
The minimum insulation resistance value accepted in each of the above tests is 2M. A 500V Insulation Resistance Test is suitable for 110 – 400 Volt transformers.
Class 2 Transformer
Double Insulated Symbol
Insulation Resistance Test Between Windings
The minimum insulation resistance value accepted in the test is 2 M.