Tufnol materials are synonymous with the electrical industry. From the early pioneering days of insulation to the present day, Tufnol has played an enormous part in ensuring safety in the critical operation of low, medium and high voltage electrical equipment.

Insulating Composite Materials - Electrical

With over 80 years of experience in the electrical industry, our paper based phenolic, fine weave cotton epoxy, and woven glass epoxy grades all possess excellent dielectric strength in the most demanding environments.

Paper based phenolic resin laminate grade

Originally developed for use as a superior rigid electrical insulation material in heavy duty switchgear in the 1920’s, our famous Kite Brand Tufnol is still manufactured today in large quantities to satisfy the requirements of today’s modern electrical industry.

It is the most widely used of all Tufnol phenolic paper grades and is put to use in a multitude of different applications including busbar supports, coil formers, insulating sleeves, mounting panels, insulated enclosures and a myriad of punched parts.

High insulative resistance

Outstanding electrical strength

Low water

Excellent dimensional stability

Products & Applications:

  • Insulation tubes
  • Standoff insulators
  • Slot wedges
  • Busbars supports
  • Washers/Top hat insulation sleeves
  • Electrical transformer insulation panels
  • Material solutions for wide range of electrical applications
  • Insulation barriers
  • Electromagnetic motors/rotating machines
  • Pre-impregnated material
  • Bespoke Machined components
  • Switch gear panels

Materials & Grades:

Fine weave cotton epoxy grade

Our superior epoxy cotton laminate, Tufnol Grade 6F/45, has a unique combination of properties.

Using a specially modified epoxy resin system, this electrical insulating material possesses high insulation resistance and electrical strength and an exceptional resistance to surface electrical tracking. This truly sets it apart from the standard paper or cotton phenolic resin laminate grades.

This versatile grade is mechanically strong, has low water absorption and excellent dimensional stability which enables it to be machined to a superb finish and very close tolerances – not surprising therefore that it is generally regarded as the ‘Rolls-Royce’ of cotton laminates!

Dangers of Electrical Tracking or ‘Treeing’

Insulator tracking refers to partial electrical breakdown along the surface of electrical insulating materials, and the formation of permanent partially-conductive paths (“tracks”) across a portion of the insulator surface. Tracking typically occurs across an insulating surface that has been subjected to prolonged high-voltage stress without the correct selection of insulating material. As these tracks develop, they often resemble ‘tree’ patterns on the insulation material.

Over time this tracking can lead to an electrical arc between conductors which can cause catastrophic failure of equipment and likely result in a fire. Thus it is vital that materials used for electrical insulation are appropriate for the equipment.

Woven glass epoxy grade

The woven glass epoxy grades in the Tufnol range are truly high performance in terms of electrical strength. Using a variety of advanced resin formulations, our group of materials in this range are characterised by very high strength properties and dimensional stability.

The range includes grades with exceptional temperature resistance, first class dielectric properties, good resistance to surface tracking, assessed flammability and superb structural strength and toughness. These high performance materials are used in applications such as insulation in large turbine generators, components in cryogenic superconducting magnets, jigs for electrochemical machining, rail/fishplate insulation, and structural insulation for electronic equipment.

Speak to the team