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Guide on PVC Vs. Silicone Test Leads and Cable

WTS
06 September 2019 10:30

 

Complete Guide: PVC Vs. Silicone Test Lead Cables

There are many different variations of electrical cable for different electrical requirements. Whether it's the cable size/gauge, voltage rating or insulation material, these variables influence cable quality and performance for a specific electrical application. Warwick Test Supplies specialises in leads and cable for test and measurement and offers a wide range using both PVC and Silicone.  This guide aims to explain the differences between these popular insulating materials. Discover what test lead cable is best for your intended purpose with this cable insulation guide. 

1 - What is PVC Cable Insulation?

2 - What is Silicone Cable Insulation?

3 - What Are The Advantages and Disadvantages of PVC Test Lead Cable?

4 - What Are The Advantages and Disadvantages of Silicone Test Lead Cable?

5 - Differences Between PVC and Silicone Cable Insulation

 

1 - What Is PVC Cable Insulation?

The full name of PVC is Polyvinylchloride, and the main ingredient is Polyvinyl chloride. PVC is an amorphous white powder that can be manufactured to be a hard or flexible end product. Stabilizers and additives are added during manufacture in practical applications to improve the end materials stability to heat, light, elasticity and flexibility. PVC used to be the world’s largest production of universal plastic and was first used as a cable insulation material during the second world war to replace rubber.  PVC is hard wearing, long lasting, uses less energy to process compared to other plastics flexible and is recyclable. PVC cable insulation does not harden and crack over time.

2 - What Is Silicone Cable Insulation?

Silicone Cable Insulation is a type of Silicone Rubber that contains; Silicone together with carbon, hydrogen and oxygen. Silicone Rubbers were first used as a cable insulation in the 1940's but at the time struggled to become popular as it had limited thermal and strength properties as well as difficulties in the manufacturing process.  These limitations have long since been overcome.  With the use of additives and fillers silicone rubber has become a popular insulation material as it is generally non-reactive, stable and resistant to extreme environments. Due to these properties and its current ease of manufacturing and shaping, silicone rubber can be found in many electrical related components.   

3 - What are the Advantages & Disadvantages of PVC Test Lead Cables?

PVC cables are traditionally the most popular cable type for electrical applications as they provide durable performance, are long lasting (25-30 years) and have low cost. The PVC material has good resistance to chemicals, corrosion, impact, abrasion and weathering.  It is these characteristics that make it suitable and widely used in test lead cables.  The addition of plasticisers to PVC being used in test lead cable also increases its flexibility from standard PVC cable making them easy to use in a test environment.  The insulation is hard and is does not suffer from static which means that dirt and grit is not attracted to it.  This allows them to stay cleaner and nicer to handle over longer periods of time.   

Despite it still being the most popular cable type, PVC cables do have some disadvantages. Although flexible, PVC cable is still not as flexible as silicone. This can be an important factor if required to make connections in very tight and bent enclosed spaces, however this downside is generally not a problem for test leads, mainly being used in open or wider spaces.   The second noticeable disadvantage of PVC is that it is less resistant to heat (-40 to 105°C) than Silicone. Accidental scorch damage from soldering in manufacture or excess current and resistance on live PVC cables can result in heat marking of the PVC or in its worst case catch fire.   

 

4 - What are the Advantages & Disadvantages of Silicone Test Lead Cables?

Silicone insulated cables have an outstanding thermal range ( -90°C - 200°C+) and being rubber based are highly flexible. Silicones superior flexibility over PVC makes it attractive as insulation for test lead cable.  Silicone insulated test leads also have a high resistance against oils and solvents, making them a favourite for harsh industrial environments.  The material is soft to touch and has a pleasant feeling in the hand.

However, silicone insulated test lead cables also have disadvantages. They are more expensive than PVC test lead cable and this price difference has increased due to a shortage of available silicone in the world.  The rubber and soft nature means that they are less hard wearing than PVC and can abrade or be cut easily.  Silicone attracts static, so they have a tendency to pick up dirt and grit quickly making them dirtier and less nice to handle than other leads.  

5 - Differences Between PVC and Silicone Cable Insulation

  • PVC Cables are considerably cheaper than Silicone Cables
  • Silicone Cables offer greater flexibility than PVC Cables
  • Silicone Cables have a superior thermal range (greater fire resistance) than PVC Cables
  • PVC Cables do not create static and are easier to keep clean than Silicone Cables

It’s clear from the outset that both cable insulation types offer good performance for test lead cable. However, like any electrical component each cable insulator has its advantages and disadvantages. Cable performance heavily depends on what cable type is used in a specific electrical application. The characteristics of the cables are different and so are the scenarios they’re best suited to. Unfortunately, it's not as simple as a ‘one type fits all’ approach. Warwick Test Supplies would advise matching cable characteristics with the intended electrical application. Contact Us if you’re unsure and we’ll advise where possible.

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