Как выбрать термоусадочную трубку

Choosing the wrong термоусадочная трубка is one of the most common and costly mistakes in wire harness assembly. Too large and the tube won’t grip the cable. Wrong material and it fails at operating temperature. Non-adhesive where sealing is required, and moisture corrodes the connector within months.

How to choose Heat Shrink Tube?This guide gives you a clear, step-by-step process to specify the correct heat shrink tube for any application — from basic wire insulation to aerospace-grade mil-spec harnesses.

Step 1 — Determine the Required Shrink Ratio

The shrink ratio is the ratio of the tube’s supplied (expanded) inner diameter to its recovered (shrunk) inner diameter.

How to Calculate the Right Size

1. Measure the substrate OD (the outer diameter of the wire, cable, or bundle you are covering)
2. Select a tube where:

• Supplied ID ≥ 1.1× substrate OD (so you can slide it on easily)
• Recovered ID ≤ 0.9× substrate OD (so it grips firmly after shrinking)

Example: Cable OD = 8mm. You need a 2:1 tube with a supplied ID of at least 9mm (= 8 × 1.1) and a recovered ID ≤ 7.2mm (= 8 × 0.9). A tube with 12mm supplied ID and 6mm recovered ID works perfectly.

Step 2 — Select the Right Material

Material selection is the most technically critical decision. The wrong material will fail in service regardless of how well sized the tube is.

Polyolefin — The Standard Choice

• Operating temp: от -55°C до +135°C
• Use when: General wiring, automotive interiors, industrial controls, low-to-medium temperature environments
• Compliance: UL 224, RoHS/REACH
• Why choose it: Lowest cost, widest availability, good insulation and flame retardancy

PVDF (Kynar) — The Aerospace/Military Choice

• Operating temp: от -55°C до +175°C
• Use when: Aerospace wiring, military harnesses, fuel or hydraulic line protection, motorsport
• Compliance: MIL-DTL-23053/16, AMS-DTL-23053
• Why choose it: Higher temperature, chemical resistance to fuels/oils/hydraulic fluids, low smoke emission

PTFE — The Extreme Environment Choice

• Operating temp: от -65°C до +260°C
• Use when: Engine-bay wiring exposed to extreme heat, chemical processing equipment, laboratory instruments
• Compliance: МИЛ-ДТЛ-23053/12
• Why choose it: Maximum temperature resistance, near-universal chemical compatibility

Elastomer — The Flexibility Choice

• Operating temp: от -75°C до +150°C
• Use when: Robotics joints, motorsport cables with movement, portable military equipment, cryogenic lines
• Why choose it: Remains rubber-like and pliable after shrinking — will not crack under flex or vibration

Dual-Wall Adhesive-Lined — The Sealing Choice

• Operating temp: -55°C to +110°C (polyolefin base) or +175°C (PVDF base)
• Use when: Marine, outdoor, underbody automotive, any installation exposed to moisture or where IP67/68 sealing is needed
• Why choose it: Adhesive flows during shrinking and seals all gaps against moisture, dust, and contaminants

Step 3 — Confirm the Diameter (Supply and Recovery)

Every reputable manufacturer publishes a size chart with:

• Supplied (expanded) ID — the diameter before shrinking
• Recovered ID — the diameter after full shrinkage
• Supplied wall thickness
• Recovered wall thickness

Common Size Ranges

Always confirm using the manufacturer’s actual datasheet — published dimensions vary between brands and product series.

Step 4 — Check Wall Thickness Requirements

Wall thickness affects the level of mechanical protection and the minimum bend radius of the installed assembly.

• Thin wall (0.3–0.5mm recovered): Lightweight wire identification, color coding, basic insulation where mechanical protection is not required
• Standard wall (0.6–1.0mm recovered): Most general wiring harness applications
• Heavy wall (1.2–2.0mm recovered): Cable joints, high-voltage terminations, areas with abrasion risk, cable repair
• Dual-wall with adhesive: Effectively adds 0.5–1.5mm of adhesive layer in addition to outer wall

Step 5 — Verify Specification and Compliance Requirements

For regulated industries, the product must comply with specific standards. Always confirm the required specification before purchasing.

Quick-Reference Selection Checklist

How to choose Heat Shrink Tube?You need a selection Checklist

☐ 1. What is the substrate OD?

       Substrate OD: _____ mm

       → Calculate: Supplied ID ≥ 1.1× OD; Recovered ID ≤ 0.9× OD

☐ 2. What is the operating temperature?

       Max continuous temp: _____ °C

       → Polyolefin (≤135°C) / PVDF (≤175°C) / PTFE (≤260°C)

☐ 3. Are there chemical exposures?

       Fuel / oil / hydraulic fluid / acid / solvent: yes / no

       → Polyolefin: no chemical exposure

       → PVDF or PTFE: fuel/oil/chemical environments

☐ 4. Is moisture sealing required?

       → Dual-wall adhesive-lined: yes / no

☐ 5. Is flexibility required after installation?

       → Elastomer type: yes / no

☐ 6. What specification must the product meet?

       → UL 224 / MIL-DTL-23053/12 or /16 / AMS / IEC 60684

Common Selection Mistakes to Avoid

Mistake 1 — Choosing a tube that is too large

If the recovered ID is larger than the cable OD, the tube will not grip the cable. The cable will slide inside and protection is compromised.

Mistake 2 — Using polyolefin in high-temperature zones

Polyolefin softens above 135°C. For engine bays, exhaust-adjacent routing, or high-power electronics enclosures, switch to PVDF or PTFE.

Mistake 3 — Skipping dual-wall in outdoor/marine applications

Single-wall tubing does not seal. In wet environments, moisture will wick along the cable jacket into the connection, causing corrosion within weeks.

Mistake 4 — Not accounting for axial shrinkage

Heat shrink tube also shrinks axially (lengthwise) by approximately 5–10% during installation. Always cut the tube longer than the area you need to cover.

Mistake 5 — Applying heat unevenly

Start heat application at the center of the tube and work toward the ends. Heating from one end traps air and causes bubbles or uneven shrinkage.

Дополнительные ресурсы

• Heat Shrink Tube Category Guide — Overview of all types and materials
• Руководство по материалам для термоусадочных трубок — Детальное сравнение материалов
• Применение термоусадочных трубок — Industry use cases
• Heat Shrink Boots Selection Guide — For connector backshell coverage

Часто задаваемые вопросы

What shrink ratio is best for general wiring?

A 2:1 shrink ratio is suitable for the vast majority of wire and cable insulation applications. Choose 3:1 or 4:1 when the substrate has a wide OD range or when using dual-wall adhesive-lined tubing that needs to flow and seal properly.

How do I measure the right heat shrink tube size?

Measure the outer diameter (OD) of the cable or bundle with a caliper. Select a tube whose supplied ID is at least 1.1× your cable OD, and whose recovered ID is no more than 0.9× your cable OD.

Can I use heat shrink tube on connectors?

Yes, but for connector backshells and branch points, molded heat shrink boots (straight, 90°, Y-shape, etc.) provide a much better fit than straight tubing. See: Ассортимент термоусадочных сапог

What is the minimum temperature to shrink polyolefin tubing?

Most polyolefin heat shrink tubing begins to shrink at approximately 70°C–90°C. Full shrinkage and recovery is typically achieved at 120°C–135°C. A standard heat gun set to 150°C is sufficient for most installations.

Does heat shrink tube comply with RoHS?

Most modern heat shrink tubing products are manufactured in RoHS-compliant, lead-free grades. Always confirm with the product datasheet if your product is destined for the European market.

Related: Heat Shrink Tube Overview | Materials Guide | Applications