Medium Wall Versus Heavy Wall Heat Shrink Tubing

What the Wall Thickness Actually Buys

Wall thickness in a heat shrink tube buys three things: abrasion allowance, crush resistance and dielectric build. On the outer protection of a cable joint the first two matter and the third is usually already satisfied.

It also costs three things: money per metre, stiffness after recovery and shrink time. A heavy wall tube takes longer to reach full recovery temperature throughout its thickness.

Where Heavy Wall Earns Its Cost

• Direct buried joints where backfill stones apply point loading for decades
• Trafficked positions where cable is walked on driven over or stood on
• Mining and quarry cable subject to continuous abrasion
• Offshore decks and crane reeling cable dragged over steel structure
• Duct entries where the cable rubs at a fixed point

Where Medium Wall Is the Right Answer

• Inside enclosures cabinets and switchgear where nothing touches the cable
• Cable that must flex continuously where heavy wall stiffness is a liability
• Positions with a defined protective route such as a tray or a trough
• Where cost per metre matters and mechanical exposure is genuinely low

The Installation Difference

A heavy wall tube needs more heat time not more heat. The recovery temperature is the same as the medium wall grade in the same family. Applying a hotter flame to speed it up scorches the outer surface before the inside has recovered which is the most common heavy wall installation error.

Work steadily, keep the flame moving, and accept that a heavy wall tube takes several minutes rather than seconds.

Choosing Across the Full Matrix

Fire behaviour and wall class are independent choices in our S3 family which means you never have to compromise one for the other.