Cold Shrink Tubing – Silicone versus EPDM

June 26, 2016 by Andrew Cousins

Exatrum Cold Shrink tubing is a reliable and handy product for Electrical, industrial and communications industry
Let’s look at an introduction to the Cold Shrink tubing – Silicone and EPDM material types:

  • Application of Cold Shrink tubing
  • Durability and Performance of Cold Shrink tubing
  • Cold Shrink tubing in Electrical and Communications industry
Silicone cold shrink tubing on telecommunications cable

Silicone Cold shrink tubing – installation


Application of Cold Shrink Tubing

As you may know, the application of Cold Shrink tubing shares only a few subtle differences between the two material types – the most important being shrink ratio:


Shrink Ratio affects finished diameters of Cold Shrink tubing

Shrink Ratio affects finished diameters of Cold Shrink tubing


Silicone Cold Shrink tubing has a shrink ratio of around 3:1 when compared with EPDM which is lower at around 2:1. This is an important characteristic when considering a tubing – especially for industrial connectors – such as coaxial connectors used in RF communication. Conversely, electrical splice terminals don’t require a high shrink ratio.

Another important application consideration for Cold Shrink Tubing – which is shared between Silicone and EPDM is the construction of the supporting core. Exatrum products possess a supporting core which uses ultrasonic welding technology. This technology is only seen on premium shrink tubing which sets it apart from generic brands. Ultrasonic welding technology provides a tougher core – less susceptible to breakages during transport, and has a thinner wall allowing larger connectors into the tubing.

Both materials possess the ease of application of Cold Shrink tubing – no tools required, no hot work (flames or heat guns), safer to install and they have the Ultrasonic welded core.


Durability and Performance of Cold Shrink tubing

Cold Shrink tubing – when compared to heat shrink tubing – is an excellent and long-lasting choice for protection of electrical connections, fittings or broken conduits from outside elements. It normally far exceeds polyolefin in most applications, especially due to its constant radial pressure which polyolefin does not have. In a lot of applications we can confidently use either Silicone or EPDM but sometimes one is preferred over the other. Let’s explore some if their properties:

Exatrum Silicone Shrink Tubing is extremely resilient. When removed from its supporting core, it holds tight around the cable – even at high temperatures, after ageing and UV exposure. It is proven against water, UV, ozone, dust and fungus. However it has a low physical strength and abrasion resistance which make it more suitable for static applications.

Exatrum EPDM Shrink Tubing (Ethylene Propylene Diene monomer) is a High Performance shrink tubing which has gained its wide industry acceptance for its superior outdoor characteristics (including UV, ozone, ingress protection) and chemical resistance including acids, alkalis, detergents, ketones alcohols and polar fluids. For general outdoor use in Australian conditions, EPDM outperforms polyolefin and Silicone.






UV resistance (hardening, loss of colour, loss of stretch) ****
Naturally UV resistant
Contains additives for superior UV stability
Outdoor, overhead power lines
Water Resistance
(IP ingress protection rating also measures dust ingress)
IP68 (SGS Certified)
IP68 (SGS Certified)
Outdoor, indoor, water (low pressure)
Ozone resistance
Great Ozone resistance
Excellent Ozone resistance
Outdoor use (Rubber tubing is traditionally poorly resistant to Ozone)
Chemical resistance – Hydrocarbons (eg. Petroleum) *
Not suitable for direct contact with petroleum and some other hydrocarbons
Absorbs Hydrocarbons (swells) and loses some of its properties
Industrial use – Petrol stations, oil refineries, direct contact with fluids
Mechanical abrasion ***
Soft material makes it less abrasion resistant.
More resistant to mechanical wear or abrasion
Public access areas, moving parts, etc. Mechanical protection (eg. conduits) may be required in some cases.
Temperature *****
-60°C to over 200°C
-40°C to 150 °C
Indoor/Outdoor, Industrial Equipment, Harsh environment
Ageing ****
More long-lasting when compared to Heat Shrink tubing
Longest life compared to Silicone and Polyolefin.
Indoor, Outdoor, electrical, communications

Overall usage – General Preferences

Overhead: Can use EPDM or Silicone Cold Shrink Tubing
Underground: Prefer EPDM due to mechanical strength and friction
Mechanical parts / moving parts: EPDM Cold Shrink tubing