Tranoil Class IA

National Transformer Oils are developed from Napthenic Base Oils having excellent Electrical properties to meet British Standards and related specifications for Electrical Insulating Oil.


  • Ensures good insulation of Electrical Conductors.
  • Prevents arcing between Electrodes.
  • Minimizes di electric loss.
  • Effectively cools Transformer Coils.
  • Provides long service life.

Performance Levels

  • Meets
  • British Standards BS : 148 : 1984 Class I (Inhibited)
  • International Electro Technical Commission Standard - IEC 296 (1982) Class I A



Recommended for Electrical Insulating Oil applications such as Transformers & Oil immersed switchgear where an oil meeting BSI, IEC or other comparable specification is required by the equipment manufacturer or user.

Typical Characteristics

Characteristics Test Method Typical Value
Appearance IEC-296 Clear free from sediments and suspended matter
Density, Kg/dm3 @ 20 °C ISO - 3675 0.865
Flash Point, (PMCC) °C ISO - 2719 145
Kinematic Viscosity ISO - 3104  
cSt@ 40 °C   10.5
cSt@ -15 °C   190
Pour Point, °C ISO - 3016 <-36
Neutralization Value , mg KOH/g IEC - 296 0.008
Corrosive Sulphur ISO - 5662 Non-Corrosive
Water Content, ppm IEC 814 22 ppm
Antioxidant Additives IEC 666 0.15
Oxidation Stability (164 hrs @ 100 °C) IEC 1125A  
a) Total acidity, mg KoH per gm of oil   0.20
b) Sludge, % by mass   0.035
Break down voltage, as delivered KV IEC 156 58
Dissipation factor, at 90 °C and 40 Hz to 62 Hz IEC 247 0.002
Interfacial Tension mN/M @ 25 °C ISO 6295 47x10-3

Handling, Health And Safety
Lubricant consisting of highly refined mineral oils with specific additives. In normal conditions of use this lubricant presents no particular toxic hazard. All lubricants, of any kind should be handled with great care, particularly avoiding any contact with the skin.

Prevent any splashing and keep away from combustible materials. Store under cover and away from any risk of pollution. Disposes off the used oil correctly, don’t pour down drains, into watercourses or the soil.


Shelf Life For Our Products Is Five Years From The Production Date