Super Edge Transformer Oil BSI Inhibited is a Highly refined, naphthenic transformer oil. For use in severe conditions, such as high ambient temperatures, where oxidation-resistant and thermally stable insulating oils meeting IEC 60296-2003 Class IA or BS148:1998 Class IA  specifications are recommended. It does not contain polychlorinated biphenyls (PCBs).

There are two main types of transformer oil used in transformers

1. Paraffin based transformer oil
2. Naphtha based transformer oil

Naphtha oil is more easily oxidized than paraffin oil. But the product of oxidation – i.e. sludge – in the naphtha oil is more soluble than the sludge from the paraffin oil. Thus sludge of naphtha-based oil is not precipitated in the bottom of the transformer. Hence it does not obstruct convection circulation of the oil, means it does not disturb the transformer cooling system.

Although Paraffin oil has a lower oxidation rate than Naphtha oil, the oxidation product (sludge) is insoluble and precipitated at the bottom of the tank. This sludge acts as an obstruction to the transformer cooling system.