Heat Shrink Tubing

About Heat Shrink Tubing

Heat shrink tubing is an essential component for electrical installations, repairs, and cable management across countless applications. This versatile protective sleeving contracts when heated, creating a secure, insulating barrier around wires, cables, and connections. Whether you're working with automotive electrics, domestic installations, or industrial equipment, heat shrink tubing provides reliable protection against moisture, abrasion, and environmental damage whilst maintaining excellent electrical insulation properties.

Our range includes comprehensive assortments from trusted brands like Sealey and Draper, offering various sizes and specifications to suit different cable diameters and applications. You'll find both standard heat shrink tubing and adhesive-lined variants that provide enhanced sealing and strain relief. Available in multiple colours including black and red, these tubes help with circuit identification and professional-looking installations. Most assortments come in convenient storage cases, making them ideal for mobile tradespeople or workshop environments where organisation is key.

Heat shrink tubing works by applying heat from a heat gun or other suitable source, causing the polymer material to shrink to approximately half its original diameter. This creates a tight, protective seal around the conductor or connection point. The shrink ratio and wall thickness vary between products, with adhesive-lined options featuring an inner layer of hot-melt adhesive that melts during heating to create a waterproof seal – particularly useful for outdoor applications or harsh environments.

Jargon Buster

• Shrink Ratio: The ratio between the tubing's original diameter and its fully shrunk diameter, typically expressed as 2:1 or 3:1. A 2:1 ratio means the tubing will shrink to half its original size, whilst 3:1 offers greater flexibility for covering irregular shapes or larger connectors.
• Adhesive-Lined: Heat shrink tubing with an internal layer of hot-melt adhesive that melts when heated, creating a waterproof and environmentally sealed connection. Ideal for marine, automotive, and outdoor electrical applications where moisture ingress is a concern.
• Wall Thickness: The thickness of the tubing wall, measured in millimetres, which determines the mechanical protection and insulation properties. Thicker walls provide better abrasion resistance and insulation values.
• Shrink Temperature: The temperature range at which the tubing begins to shrink and fully recovers, typically between 90°C and 120°C for standard polyolefin tubing. This determines the heat source required for proper installation.
• Recovery: The process by which heat shrink tubing contracts to its final diameter when heated. Full recovery ensures optimal protection and insulation performance.
• Dielectric Strength: The maximum voltage the tubing can withstand without breaking down, measured in kilovolts per millimetre (kV/mm). Essential for ensuring safe electrical insulation in accordance with UK electrical standards.

Who Uses Heat Shrink Tubing?

• Electricians and Electrical Contractors: For insulating wire joints, cable repairs, and creating professional terminations in domestic and commercial installations
• Auto Electricians and Motor Mechanics: Essential for automotive wiring repairs, ECU connections, and protecting circuits from moisture and vibration
• Marine Engineers: For waterproof electrical connections on boats and marine equipment where corrosion resistance is critical
• Electronics Engineers and Technicians: For circuit board repairs, component insulation, and cable management in electronic assemblies
• Maintenance Engineers: For industrial equipment repairs, cable identification, and preventative maintenance programmes
• Audio Visual Installers: For professional cable terminations, strain relief, and colour-coded identification in AV systems
• DIY Enthusiasts and Home Improvers: For household electrical repairs, appliance fixes, and garden lighting installations
• Telecoms and Data Installers: For protecting cable joints and creating neat, professional network installations

How to Choose the Right Heat Shrink Tubing

Diameter and Shrink Ratio: Measure your cable or connection diameter and select tubing with an expanded diameter that fits comfortably over it. Remember that 2:1 shrink ratio tubing will halve in size, so choose accordingly. For irregular shapes or connectors, 3:1 ratio offers more flexibility.

Adhesive-Lined or Standard: Standard heat shrink tubing provides excellent electrical insulation and mechanical protection for most applications. However, if you're working outdoors, in marine environments, or anywhere moisture ingress is a concern, adhesive-lined tubing creates a waterproof seal that offers superior environmental protection.

Colour Coding: Black tubing is standard for general applications, but coloured options like red are useful for identifying circuits, phases, or cable functions. Many electricians maintain stocks of multiple colours to comply with UK wiring regulations and make future maintenance easier.

Wall Thickness: Thin-wall tubing suits electronic applications where space is limited, whilst medium and heavy-wall options provide better mechanical protection for automotive, industrial, or high-abrasion environments. Consider the operating conditions and physical stresses the tubing will face.

Assortments vs Individual Sizes: Starter assortments from Sealey and Draper offer excellent value and variety for general trade work, typically including multiple diameters and lengths in organised storage cases. For specific projects or high-volume work, individual rolls may prove more economical.

Temperature and Voltage Ratings: Ensure the tubing meets the temperature and voltage requirements of your application. Standard polyolefin tubing typically handles up to 125°C and provides adequate insulation for most UK 230V applications, but always verify specifications for specialised requirements.

Popular Accessories

• Heat Guns: Purpose-built tools for applying controlled heat to shrink tubing evenly without damaging cables or components
• Cable Ties and Clips: For securing and organising cables before applying heat shrink tubing
• Wire Strippers and Cutters: Essential for preparing cables and cutting heat shrink tubing to precise lengths
• Electrical Tape: Complementary product for temporary repairs or additional cable bundling
• Cable Crimping Tools: Often used alongside heat shrink tubing for creating secure electrical connections
• Heat-Resistant Mats: Protect work surfaces when using heat guns or other heating sources
• Digital Multimeters: For testing connections and ensuring proper insulation after applying heat shrink tubing
• Solder and Soldering Irons: Frequently used in conjunction with heat shrink tubing for permanent electrical connections

Safety Information

When working with heat shrink tubing, always ensure electrical circuits are isolated and de-energised before beginning work. Follow proper isolation procedures and use appropriate voltage testers to confirm circuits are dead, in accordance with HSE electrical safety guidelines.

Heat guns and other heating sources reach extremely high temperatures and pose burn risks. Always direct heat away from yourself and others, work in well-ventilated areas, and allow equipment to cool completely before storage. Never use naked flames such as lighters, as these can damage the tubing, cables, and surrounding materials whilst creating fire hazards.

Ensure heat shrink tubing is rated for the voltage and current of your application. Using undersized or incorrectly rated tubing may result in inadequate insulation, creating shock hazards or fire risks. When working to UK wiring regulations (BS 7671), verify that your choice of heat shrink tubing provides appropriate insulation for the circuit voltage.

Wear appropriate PPE including safety glasses when cutting tubing and heat-resistant gloves when operating heat guns. Fumes from heating polymer materials should be avoided – always work in well-ventilated spaces and take regular breaks when completing large-scale projects.

Frequently Asked Questions

Can I use a hair dryer instead of a heat gun to shrink heat shrink tubing?

Whilst a hair dryer produces heat, it typically doesn't reach sufficient temperatures (usually only 60-80°C) to properly shrink most heat shrink tubing, which requires 90-120°C. A proper heat gun ensures even, complete shrinkage and proper adhesive activation on lined tubing. For occasional use, some lighter-duty tubes may respond to prolonged hair dryer application, but a heat gun is essential for professional results.

What's the difference between 2:1 and 3:1 shrink ratio?

A 2:1 shrink ratio means the tubing will shrink to half its original diameter, suitable for most standard cable applications. A 3:1 ratio shrinks to one-third of its original size, offering greater flexibility for covering irregular shapes, large connectors, or transitions between different cable diameters. The 3:1 ratio provides a tighter final fit but costs slightly more.

How do I know what size heat shrink tubing I need?

Measure the diameter of your cable or connection at its widest point. Choose tubing with an expanded (pre-shrunk) diameter at least 20-30% larger than this measurement to ensure easy application. After shrinking, the tubing should fit snugly without gaps. For example, a 10mm cable would typically require 12-13mm expanded diameter tubing with a 2:1 shrink ratio.

Is heat shrink tubing waterproof?

Standard heat shrink tubing provides good moisture resistance but isn't fully waterproof. For genuine waterproof applications such as outdoor installations, marine environments, or underground cables, use adhesive-lined heat shrink tubing. The internal hot-melt adhesive creates a complete environmental seal when heated, preventing moisture ingress and providing superior corrosion protection.

Can heat shrink tubing be removed and reused?

Heat shrink tubing cannot be "unshrunk" and reused. Once heated and shrunk, it's permanently set. To remove it, you'll need to carefully cut it away using wire strippers or a sharp knife, taking care not to damage the underlying cable. This is why proper sizing and positioning before heating is essential for professional installations.