SLEEVANTA / Buyer guide
How to choose heat-shrink tubing size
Use pass-over diameter, recovered diameter and the exact model's tolerances to shortlist heat-shrink tubing for a cable, splice or connector.
The short answer
What size heat-shrink tubing do I need?
Choose tubing whose minimum expanded inside diameter clears the largest part it must pass over, and whose maximum fully recovered inside diameter is smaller than the area it must grip. Check both dimensions in the exact model's size table; the shrink ratio alone does not establish fit.
Measure the whole installation path
Record the largest connector, splice or component the unshrunk tube must pass over, then the smallest cable or substrate diameter it must grip. Include tolerances, irregular shapes and space needed to slide the tube into position.
- Largest pass-over outside diameter, in mm
- Smallest and largest installed substrate diameters, in mm
- Required coverage length and space near heat-sensitive components
- Cable jacket or substrate material and operating conditions
Compare guaranteed dimensions, not just the ratio
Read the manufacturer's minimum expanded ID and maximum fully recovered ID for the quoted size. Ask for the recovered wall thickness and longitudinal change if they affect clearance, insulation or coverage. Do not specify a universal clearance percentage without the model's installation guidance.
A nominal 2:1 ratio describes an expanded-to-recovered diameter relationship. It does not mean every tube labeled 6 mm has the same tolerance or that its wall will be suitable for your assembly.
A sizing example—not a part recommendation
Suppose a tube must pass over a 9 mm connector and grip a 4 mm cable. A hypothetical table entry with a minimum expanded ID of 12 mm and a maximum fully recovered ID of 4 mm would clear the connector, but it does not establish an interference fit on the 4 mm cable. Shortlist an exact model with a lower recovered ID, then verify wall thickness and application limits.
For non-round components, do not treat a single outside-width measurement as a complete fit check. Send a drawing or dimensions and evaluate a sample before accepting the size.
Validate the sample on your assembly
Confirm installation temperature and heating method against the manufacturer's instructions and the cable or connector's heat tolerance. Check final coverage, grip, wall thickness and any adhesive behavior. A good dimensional fit alone does not establish a flame rating, voltage rating or waterproof assembly.
Related questions
Can I select tubing using only my cable diameter?
Only if the full installation path and required recovered fit are already known. A larger connector or splice may determine the expanded size, while the cable determines the recovered fit.
Does the tube need to reach its fully recovered diameter?
The fully recovered ID is a size-table limit used for selection. The installed tube may stop recovering when it meets the substrate. Check the manufacturer's recommended application range and required wall thickness.
Reference basis and scope
This guide draws on SLEEVANTA’s reviewed family references and sourcing workflow. It is not an independent laboratory test or an exact-part approval. For the referenced technical ranges and limitations, see:
- HS-SW2 — product-family reference
- HS-DW3 — product-family reference
- Source media, document scope and trading disclosure
Request the current manufacturer’s dimensional table, installation guidance and required evidence for the exact proposed model before approving a substitution or order.