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PET braided sleeving is widely used in automotive wiring, electronics, industrial equipment, robotics, rail transit, cable management and more. Because the material is flexible and the structure is expandable, engineers and buyers often ask:
“How do I select the correct sleeve size?”
“What tolerance should I expect?”
“Will the sleeve fit after my cables are bundled?”
the following explains how PET braided sleeving tolerances work and how to choose the correct specification based on your application.
Unlike hard plastic or metal tubes, PET braided sleeving has unique characteristics:
Diameter changes when stretched
Longitudinal stretch → diameter decreases
Lateral expansion → diameter increases
Naturally allows a wider tolerance range
Measurement varies depending on tension and measuring angle.
Tight weave → smaller tolerance, higher coverage
Loose weave / expandable weave → larger tolerance, greater expansion range
Braiding speed, tension, and filament thickness all impact the final size.
Therefore, PET sleeving dimensions should be defined as:
“Nominal size + expansion range + standard tolerance.”
PET sleeving sizes are usually defined using:
Examples:
Flat width 10 mm → fits round diameter approx. 6–8 mm
Flat width 16 mm → fits round diameter approx. 10–14 mm
Typical expansion performance:
Minimum usable diameter ≈ 0.6 × nominal diameter
Maximum expansion ≈ 1.8 × nominal diameter (or more depending on weave)
Tolerance values vary by manufacturer, but common industry ranges are:
| Nominal Size (mm) | Typical Tolerance | Usable Cable Ø Range |
| 3 mm | ±0.5 mm | 2–5 mm |
| 6 mm | ±1.0 mm | 4–12 mm |
| 8 mm | ±1.0 mm | 5–14 mm |
| 10 mm | ±1.5 mm | 6–18 mm |
| 12 mm | ±1.5 mm | 8–20 mm |
| 16 mm | ±2.0 mm | 10–28 mm |
| 25 mm | ±3.0 mm | 16–45 mm |
| 32 mm | ±3.5 mm | 20–55 mm |
High-density, flame-retardant or thickened versions may have smaller tolerances; expandable versions allow larger ranges
Include:
Cable outer diameter
Connectors
Taping or insulation bulges
Branching points
Always use the maximum diameter when selecting the size.
A practical rule:
Example:
Cable bundle max Ø = 10 mm
Usable sleeving sizes = 8 mm, 10 mm, 12 mm
For tighter fit → choose 8 mm
For easier installation → choose 10 mm
For passing connectors → choose 12 mm
Choose tight-weave / high-density PET sleeving
Used in:
Automotive harness
Industrial robots
High-friction environments
Mechanical cables
Advantages:
✔ Smaller tolerance
✔ Better protection
✔ Higher abrasion resistance
Choose standard expandable sleeving
Advantages:
✔ Greater expansion range
✔ Easier installation
✔ Fits multi-branch bundles
✔ More cost-effective
Choose anti-rodent sleeving
Typically tighter weave and smaller tolerance.
Front-loading (before connectors are applied)
→ Slightly tighter size is acceptable
Rear-loading (connectors already attached)
→ Need a larger expansion range or one size up
UL94 V0 flame-retardant PET → tighter weave
High-temperature PET → stiffer yarn, more stable tolerance
Automotive or military standards → specific tolerance tables
To ensure consistent quality, companies should establish the following practices:
Define:
Flat-width measuring method
Diameter measuring tension
Natural vs expanded state
Example:
Sleeve Ø10 mm (usable range: 6–18 mm)
This is more practical than only stating a linear tolerance.
Natural state
Light stretch
Maximum expansion
This reveals actual performance in real use.
Braiding density
PET monofilament diameter (0.20 / 0.25 mm)
Machine tension and speed control
These factors directly impact tolerance.
Helps detect production drift before defects occur.
To choose the right PET sleeving size:
Example: 12 mm
12 mm size → covers 8–20 mm
16 mm size → covers 10–28 mm
Need to pass connectors → choose 16 mm
Need a tight, neat appearance → choose 12 mm