A Complete Guide to Heat Shrink Tubing

We explain all about heat shrink tubing, including the different types, sizes, materials, and certifications.

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What is Heat Shrink Tubing?

Heat shrink tubing is a versatile plastic layer which can be applied to cabling and components for several purposes by electricians, engineers and similar professionals, including:

  • Electrical insulation - for example, to repair a damaged or exposed length of wire

  • Protection – from dust, chemicals, moisture or abrasion

  • Reinforcement – relieving the strain applied by cables held at tension

  • Bundling multiple wires into a single unit

  • Identification – the wide range of available colours allow for easy coding

They are also known as heat shrink sleeves, in particular when used with cables.

The name refers to the fact that the tubing is designed to shrink into place and become rigid when heat is applied, providing a durable, protective coating.

Given the range of possible uses, heat shrink tubing is available in a variety of materials, sizes and colours. Some also come with an adhesive liner to help the tubing stay in place once applied.

Watch out for the ‘shrink ratio’ – the relationship between the original size of the heat shrink tube and its shrunken form following application. This is usually either 2:1 or 3:1, with higher numbers indicating a greater ratio and therefore a tighter fit. For example, tubing with a 2:1 ratio will shrink to half its size and a 3:1 ratio indicates shrinkage to one third the full size.

How to Use Heat Shrink Tubing Safely

It is important when using heat shrink tubing to proceed with caution and observe basic safety measures to avoid accidents or injuries. Here’s how to use heat shrink tubing:

  1. Begin by choosing the right size tubing with the correct shrink ratio. It should comfortably cover the wire or components before it has been shrunk into place to ensure a tight fit afterwards. Remember that it will be across both its breadth and its length

  2. If the components to be covered could change size after application, ensure that the tubing has sufficient expandability by comparing its diameter when shrunk (called the ‘recovered’ diameter) with its size before shrinking (called the ‘expanded’ diameter). Check the recommended heating temperature for the tube to avoid uneven application or melts

  3. Cut a suitable length of tubing using standard scissors and lay or slide this over the target components. It’s now time to heat the shrink wrap. This can be done with a hand held heat gun or a heat shrink oven. The latter are specialist appliances for more precise and advanced heat application

  4. If you use a gun, move the heat back and forth across the tubing and avoid staying in one place to minimise the risk of burns. Continue until the wrap has been tightly secured

Common Heat Shrink Tubing Materials

Heat shrink tubing works thanks to the responsiveness of the multiple materials used to make the product. Each has different strengths and properties.

Heat Shrink Materials

Polyolefin Heat Shrink Tubing

The synthetic polymer polyolefin is the most widely used heat shrink tubing material due to its resistance to high temperatures and chemical contamination.

heat-shrink

PVC Heat Shrink Tubing

Polyvinyl chloride or PVC is another widely used material in heat shrink tubing. It is versatile and provides a smooth surface.

PVC Heat Shrink Tubing

PTFE Heat Shrink Tubing

Polytetrafluoroethylene or PTFE is best known under the brand name Teflon®. When used in heat shrink tubing, this synthetic compound is highly resistant to chemicals and has an exceptionally low coefficient of friction, meaning that substances will slide off it very easily.

PTFE Heat Shrink Tubing

FEP Heat Shrink Tubing

Fluorinated ethylene propylene (FEP) heat shrink tubing is highly resistant to chemical spillage, making it a good choice for sealant applications. It shrinks at a lower temperature than PTFE.

FEP Heat Shrink Tubing

Elastomeric Heat Shrink Tubing

Elastomeric heat shrink tubing is noted for its flexibility as well as its resistance to abrasion and hazardous liquids like diesel fuel and hydraulic fluid. It is widely used in industrial environments to protect cabling.

Elastomeric Heat Shrink Tubing

PVDF Heat Shrink Tubing

Polyvinylidene fluoride or PVDF heat shrink tubing is noted for its high level of resistance to flame, corrosive chemicals and industrial fuels. It is very robust and will not perforate easily.

PVDF Heat Shrink Tubing

Silicone Heat Shrink Tubing

Silicone heat shrink tubing is noted for its flexibility and resilience when exposed to very high or very low temperatures. It is an excellent choice for insulation heating elements and bundling fibre optic cables. It is also widely used in medical environments because it withstands sterilisation conditions well.

Silicone Heat Shrink Tubing

Viton Heat Shrink Tubing

Viton heat shrink tubing is made from fluoroelastomer, a type of synthetic rubber. It is resistant to high temperatures and remains flexible even at low temperatures. It forms an effective seal against oils, fuels and lubricants of various kinds.

Viton Heat Shrink Tubing

Types of Heat Shrink Tubing

Heat shrink tubing is available in two basic types, single or dual wall, also known as thin or double wall.

Single or thin wall tubing is reliable and physically robust. It is a good choice when electrical insulation or protection against abrasion and strain is required.

By contrast, double or dual wall tubing is a better choice in situations where protection from corrosion or a firm seal is the primary aim. An additional adhesive layer within the tubing provides protection against moisture.

Heat Shrink Accessories

Here are some of the most commonly used heat shrink products and accessories:

Heat Shrink Accessories

Heat Shrink Connectors

Heat shrink connectors or splices are a form of tubing used to join cabling together or to connect it to power outlets. They are available in various sizes and colours. Typically made from versatile materials like polyolefin, they usually feature a dual wall design, with a shrinkable outer layer and an inner which will melt into place when heat is applied to create a strong, watertight seal.

Heat Shrink Connectors

Heat Shrink Wrap

As the name suggests, heat shrink wrap is a variant of heat shrink tubing made to wrap around cabling during repair and splicing operations. Typically it has a shrink ratio of 3:1 and provides a firm a seal resistant to moisture, chemicals and fungal contamination.

Heat Shrink Wrap

Heat Shrink Tape

Heat shrink tape works on similar principles to tubing and is typically used in conjunction with it for insulating seals and enclosures.

Heat Shrink Tape

Heat Guns

Electric heat shrink guns are the principal method of applying heat to tubing, wrap and tape. These versatile appliances are lightweight and available with both single and double handles.

Heat Shrink Guns
    Related Uses
  • Stripping Paint
  • Thawing Pipes
  • Removing Decals
Browse Heat Shrink Guns

Heat Shrink Products in Action

Take a look at this handy video to learn more about the various uses and properties of heat shrink.

Additionally, make the most of the opportunity to see some heat shrink products from TE Connectivity in action!

What Size Heat Shrink Tubing Do You Need?

Determining what size heat shrink tubing you will need begins with the diameter of the materials to be covered.

  1. Measure the widest part of the cabling or components you plan to apply the tubing to

  2. Select tubing that is approximately 20-30% larger than the measurement taken in step one. To choose the right tubing, you will need to know:

    • Its shrink ratio. As mentioned above, a 2:1 ratio indicates that the tubing will shrink to approximately half its size when heat is applied, while a 3:1 ratio means that it will shrink to one third its full size

    • The thickness of the tubing walls. This is normally measured in millimetres or inches

    • The ‘inside diameter’ (ID) of the tubing following shrinkage as well as its ‘expanded inside diameter’ (expanded ID) before shrinkage. The latter measurement will be the one displayed on the labelling. A variation of this – the ‘lay flat width’ – will also sometimes need to be considered. This is simply the width of the tubing when laid flat

  3. Consider the length of the tubing. This will decrease somewhat when shrunk – normally between five and ten per cent - and this should be taken into account when selecting the length of tubing in order to ensure full coverage

What Size Heat Shrink Tubing Do You Need?

  • 5mm tubing with a .198 inch diameter is the recommended heat shrink tubing size for 12 gauge wire

  • The recommended heat shrink tubing size for 14 gauge wire is the same as that for 12 - 5mm, with a .198 inch diameter

  • For 16 gauge wire, 3mm heat shrink tubing with a 2:1 shrink ratio and a .118 inch diameter is recommended

  • The recommended heat shrink tubing size for 18 gauge wire is the same as that for 16 gauge wire: 3mm with a 2:1 shrink ratio and a .118 inch diameter

Heat Shrink Standards and Certificates

These are the principle standards and certificates for heat shrink tubing:

UL224-2010

UL224-2010 specifies requirements for round insulating tubing made from polymers with heat-setting, heat-responsive and elastic properties.

SAE AS23053

SAE AS23053 sets out requirements for electrical insulating sleeving that will shrink to a predetermined size when heat is applied.

ASTM D 2671

ASTM D 2671 specifies standard methods of testing heat shrink tubing intended for use with electrical cabling.

ASTM D3150

ASTM D3150 is a specification that applies to heat shrink made from PVC when used for electrical insulation.

FAQs

Can You Cut Heat Shrink Tubing?

Yes. Standard scissors and a ruler will be adequate in most cases, unless you require an exact length of tubing, in which case use a more precise measuring tool. For thicker tubing you may require wire cutters or pliers.

Do not attempt to cut tubing lengthwise as this will affect its strength and moisture-proofing and could also encourage tearing.

Can You Use Electrical Tape Instead of Heat Shrink Tubing?

This may be possible in limited instances but electrical tape is less durable than heat shrink tubing and is also more prone to lose its adhesion over time. As a result, you may need to regularly inspect electrical tape to ensure ongoing integrity which may be impractical in some instances.

Electrical tape is quick and easy to apply but it does not offer the same level of protection against corrosion, moisture or wear, so it is not a good choice in unforgiving locations.

How Do You Remove Heat Shrink Tubing?

The first step is to locate the end of the heat shrink tubing. Then, grip this with thin pliers – needle nose pliers would be a good choice – and pull gently away from the connection. Finally, trip the tubing off using a blade while keeping the wire away from the electrical connection.

Is Heat Shrink Tubing Waterproof?

Yes, most heat shrink tubing is watertight and will also protect against other moisture and even potentially corrosive liquids.

What Temperature is Needed for Heat Shrink Tubing?

This varies according to the material used to make the heat shrink tubing. For example, polyolefin shrinks at around 90°C, while PTFE (Teflon) requires a considerably higher 250°C.