An IP68 cold shrink tube is one that seals a cable joint well enough to pass the IP68 ingress-protection test — dust-tight and protected against continuous immersion in water. VOLSUN cold shrink tubes are tested to reach IP68-class waterproof sealing when installed and verified as a qualified assembly. The rating matters most where a joint lives underground, underwater, or in constant spray — and that is precisely where cold shrink is specified. This guide explains what IP68 covers, how cold shrink earns it, and how to state the claim correctly.

What IP68 Actually Means

IP stands for ingress protection. The two digits set the bar:

• 6 — dust-tight; no ingress of dust.
• 8 — protected against continuous immersion beyond 1 m, under conditions set by the manufacturer.

The depth and duration behind that "8" are defined by the manufacturer's test, not one fixed number — so always read the tested condition. An IP68 joint keeps both dirt and water out of the contact and conductor, exactly what an outdoor or buried cable needs.

How Cold Shrink Reaches IP68

A cold shrink tube earns the rating by forming one seamless rubber seal over the joint:

• It shrinks to its own elastic memory, hugging the cable and connector with no seam to lift.
• The mastic-lined silicone grade adds a water-blocking layer right at the critical junction.
• It installs at room temperature, so there is no heat to crack the seal or scorch the dielectric.
• The recovered ID grips the jacket tightly, so water cannot track inward along the cable.

Because the seal is continuous and conforms to awkward shapes, water has no path in — which is exactly what the immersion test checks.

The Rating Is Tested as an Assembly

VOLSUN cold shrink tubes are tested to achieve IP68-class sealing — validated as a qualified assembly (cable + connector + correct install) under the relevant test standard. IP68 is an assembly rating, not a free-standing property of the bare tube, so publish the tested configuration and test basis with the claim.
In practice the IP68 result depends on the cable, the connector, the install method and the test conditions used. State those when you cite the number.

Where IP68 Cold Shrink Is Used

• Underground and direct-buried joints — constant soil moisture, no second chance to re-seal
• Submarine and underwater cable transitions
• Pole-mounted and rooftop connectors in heavy rain or coastal spray
• Tunnel and subway cable runs

VOLSUN Product Match

For IP68-class sealing, specify RUBLS-SILIC with Mastic: silicone + internal sealing mastic, dielectric ≥18 kV/mm, ~4:1 shrink, validated −40 °C to +80 °C, RoHS / REACH. The EPDM and high-expansion silicone lines cover other sites where the full IP68 immersion grade is not required.

IP68 means a dust-tight, immersion-proof joint — and VOLSUN cold shrink tubes are tested to deliver it as a qualified assembly. Tell us your cable, connector and install condition and we will match the right grade and supply the test basis. 

Need a sample or quote? Contact VOLSUN team for more details.

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