Fiberglass Sleeving vs Heat Shrink Tubing: Two Ways to Protect a Wire

When a wire needs protection, two product families cover most of the work, and they are not substitutes for each other. Fiberglass sleeving is a braided, open-weave armor that slips over a wire and stays removable. Heat-shrink tubing is a conformal layer that shrinks onto the wire and becomes part of the assembly. The right choice depends on what the wire actually faces.

What each one is made for

When to pick fiberglass sleeving

• High heat: motor leads, ovens, exhaust-adjacent wiring, transformers
• Abrasion zones where a braided armor outlasts a film tube
• Sites where heating is not practical or not allowed
• Harnesses that must be opened for service - sleeving slides off and back on

The silicone-coated grades add a sealed outer skin to the braid, which lifts both temperature and fluid resistance. Our range covers silicone-coated sleeving, silicone-resin sleeving and fire sleeve for the hottest duties.

When to pick heat shrink

Heat-shrink is the right call when the job is electrical insulation and sealing rather than armor: the tubing conforms to the joint, keeps moisture out (adhesive-lined grades pass submersion tests), and adds dielectric strength. It is the standard for splices, terminals, and every place a wire ends. On wires that flex, a correctly sized heat-shrink tube also works as a strain-relief transition at the connector.

Combining both

On demanding harnesses the two are often used together: a heat-shrink splice inside, then a fiberglass sleeve over the whole branch for abrasion and heat. The combination costs less than a specialist high-temperature heat-shrink on every joint and is easier to service.

For the sealing side of the comparison, our dual-wall adhesive-lined tubing guide explains when the waterproof inner wall is worth the extra cost.