Selection Guide
Heat Shrink Tubing Selection Guide — Size, Ratio & Material
Complete heat shrink tubing selection guide: shrink ratio, size calculation, material selection, dielectric strength, and application recommendations.
Overview
Selecting the right heat shrink tubing requires matching shrink ratio, supplied/recovered diameters, temperature rating, and application requirements. This guide covers the complete selection process.
Selection Process
Calculate Required Sizes
Measure the largest diameter to cover (connector, splice) and the smallest wire diameter. Supplied ID must exceed largest diameter. Recovered ID must be smaller than smallest diameter.
Select Shrink Ratio
2:1 for uniform shapes. 3:1 for moderate diameter variation. 4:1+ for large connector-to-wire transitions. Higher ratios cost more but handle greater size variation.
Choose Material
Polyolefin: general purpose, -55C to +135C. Dual-wall (adhesive): waterproof sealing. PVDF: high-temp to +175C. PTFE/FEP: extreme temp/chemical to +260C.
Verify Electrical Rating
Dielectric strength (kV/mm) and voltage rating must exceed application voltage. 600V rated for most applications. 1000V+ for medium voltage.
Consider Installation
Heat gun temperature: 120-250C depending on material. Shrink temperature: check material specification. Allow cooling before handling.
Frequently Asked Questions
How do I calculate the right heat shrink tubing size?
Supplied ID > largest diameter to cover. Recovered ID < smallest diameter. Example: wire=3mm, connector=8mm -> need supplied ID >8mm AND recovered ID <3mm. A 12.7mm/4mm (3:1) or 12mm/3mm (4:1) would work.
When should I use dual-wall (adhesive-lined) heat shrink?
Any application requiring environmental sealing: outdoor, underground, marine, automotive engine bay, or anywhere moisture ingress would cause corrosion or electrical failure. Single-wall is sufficient for indoor, dry-location electrical insulation only.
Need Application-Specific Advice?
Our engineers can help you select the right product for your exact requirements.