ODC Insulation Materials

Insulation is one of the most important qualities that a transformer has, which is responsible for providing better performance when the transformer is operated. In fact, the durability and stability of a transformer highly depend upon the proper utilization of the insulation materials present within it. This means that other than metallic components like silicon steel and copper, there are also other important insulating materials used in power transformers for better functioning. You must get in touch with a reliable transformer manufacturer so that you can rest assured that the transformers you build will be of top-class quality with the best materials, both metallic and insulating, installed within. Now, let us take a look at the list of insulating materials present in a transformer.

Insulating paper

Insulating paper is made up of vegetable fibers that are felted together to form a sheet. The fibers are obtained from plants like cotton, straw, hemp, manila, and coniferous trees. When this insulating paper is put into the insulating oil under vacuum, it attains extremely high electric strength.

ODC Supplies the below Insulating Papers:

  • Kraft Paper – 0.13mm to 0.5mm thickness


  • Diamond Dot Paper – 0.13mm – 0.38mm thickness


  • Polyester Backing Paper – 0.11mm and 0.13mm


  • Nomex Polyester Nomex (NPN) – 0.23mm / 0.28mm / 0.35mm


  • Dacron Mylar Dacron (DMD) – 0.17mm / 0.23mm / 0.28mm


  • Millinex Film – 0.2mm / 0.25mm


 Insulating tape

As the name itself says, insulating tape is used for various taping purposes. These are available in a variety of forms like cotton tapes, woven tapes, glass woven tapes, and phenol laminated paper base sheet. These tapes are used in areas where high strength is required. They are also used for banding of transformer cores.

ODC Supplies the below Insulating Tape:

  • Polyester Tape – 0.135mm


  • Glass Tape – 0.09mm / 0.13mm


  • Poly-Dynamo Tape


  • Poly-Webbing Tape


  • Filament Tape


 Pressboard – Presspan - Transformer Board and G11

Used in the electrical, mechanical, and thermal designing of transformers, the pressboard is also made up of vegetable fibers that contain huge amounts of cellulose. These pressboards can be moulded into any shape to be used in transformers; the most commonly seen shapes being angle rings and caps.

ODC supplies the below Pressboards and G11

  • 1mm – 3mm Low Density (LD) Boards
  • 1mm – 10mm High Density (HD) Boards

G11 and GPO3 Boards

  • G11 Boards (Green)
    • 8mm / 1.5mm / 3mm / 4mm / 5mm / 6mm


  • GPO3 Boards (Red)
    • 8mm / 1.5mm / 3mm

Tubes/Sleeving/Dogbones and Strips

Used in the electrical, mechanical, and thermal designing of transformers. To create vent duct spacing and aid in cooling of transformers.

ODC supplies the below range of tubes and sleeving:

  • Acrylic Sleeving – Silicon based, 2kVThese are supplied in either 100m or 200m rolls
    • Sizes available 0.5mm – 12mm


  • Crepe Paper tubes – Supplied in either 1000mm or 2000mm lengths
    • Sizes available
  • 5 x 7
  • 5 x 10
  • 6 x 8
  • 8 x 10
  • 8 x 12
  • 10 x 12
  • 10 x 16
  • 17 x 21
  • 17 x 24


  • Transformer Strips
    • Supplied in 2000mm lengths
    • Full range of sizes –
    • We can manufacture any customer requirement.
  • Dogbones
    • Similar application to transformer strips
    • Supplied in 2000mm lengths
    • Available sizes:
      • 6 x 8
      • 10 x 12
      • 16 x 20

ODC South Africa has an extensive range of insulation products please free to contact us should you not find what you are looking for.