Heat Shrink Double Layer Tube (GDLT)
A co-extruded cross-linked polyolefin tube with an insulating inner layer and a semi-conductive outer layer, providing reliable shield protection at power cable joints.
- ASTM D638
- ASTM D2671
- ASTM D2240
Choose a size
Selection Chart
- D min.
- Minimum internal diameter as supplied
- d max.
- Maximum internal diameter after recovery
- T
- Recovered wall thickness
| Gala code | D min.(mm) | d max.(mm) | T(mm) |
|---|---|---|---|
| GDLT 30/11 | 30 | 11 | 5.0 ± 0.3 |
| GDLT 35/13 | 35 | 13 | 5.0 ± 0.3 |
| GDLT 45/16 | 45 | 16 | 5.0 ± 0.3 |
| GDLT 55/20 | 55 | 20 | 5.0 ± 0.3 |
| GDLT 65/27 | 65 | 27 | 5.0 ± 0.3 |
| GDLT 85/30 | 85 | 30 | 7.5 ± 0.3 |
| GDLT 100/35 | 100 | 35 | 7.0 ± 0.3 |
| GDLT 120/45 | 120 | 45 | 7.0 ± 0.4 |
Standard colour: black/red. Source: GALA Insultube Double Layer Tube (GDLT) catalogue sheet, Issue 2, January 2024.
Material properties
Technical Specification
| PROPERTIES | INNER INSULATION LAYER | OUTER SEMI-COND. LAYER | STANDARD |
|---|---|---|---|
| Value | |||
| Physical | |||
| Tensile Strength | 12 Mpa(N/mm²) (min.) | 12 Mpa(N/mm²) (min.) | ASTM D638 |
| Ultimate Elongation | 300% (Min.) | 300% (Min.) | ASTM D638 |
| Longitudinal Change | -10% (Max.) | -10% (Max.) | ASTM D2671 |
| Hardness | 50 ± 3 Shore D | 50 ± 3 Shore D | ASTM D2240 |
| Water absorption | 0.5 % (max.) | 0.5 % (max.) | ASTM D570 |
| Thermal | |||
| Accelerated ageing | ( 120⁰C for 500 Hrs) | ( 120⁰C for 500 Hrs) | ASTM D2671 |
| Tensile Strength | 10.5Mpa (N/mm) (min.) | 10.5Mpa (N/mm) (min.) | ASTM D638 |
| Ultimate Elongation | 270 % (min.) | 270 % (min.) | ASTM D638 |
| Low Temperature Flexibility | No Cracking | No Cracking | ASTM D2671 |
| -40⁰C for 4 hrs.) | |||
| Heat Shock (250⁰C for 30 min.) | No cracking or flowing | No cracking or flowing | ESI 09-11 |
| Shrink Temperature | 135⁰C | 135⁰C | IEC 216 |
| Continuous Temperature limit | -40 to +100⁰C | -40 to +100⁰C | IEC 216 |
| Electrical | |||
| Dielectric Strength | 20 KV/mm.(min) | N/A | ASTM D149 |
| Volume Resistivity | 1 × 10¹⁴ Ohm.cm (min) | 1 × 10³ Ohm.cm (min | ASTM D257 |
Dimensions & Drawings
GDLT co-extrudes an insulating inner layer with a semi-conductive outer layer in cross-linked polyolefin, giving reliable shield protection at power cable straight-through joints up to 36 kV.
Covered on this page
- Heat Shrink Double Layer Tube-GDTL Tube
Features & Benefits
- Co-extrusion technology combines an insulating layer with a semi-conductive outer layer
- Operating temperature range -40°C to 100°C
- Minimum shrink temperature 100°C; minimum full shrink temperature 130°C
- Standard colours black/red
Applications
- Insulating and outer-shielding layer in power cable straight-through joints up to 36 kV
- Any application requiring combined insulation and shielding
Standards & Compliance
- ASTM D638
- ASTM D2671
- ASTM D2240
- ASTM D570
- ASTM D149
- ASTM D257
- ESI 09-11
- IEC 216
FAQs
Frequently Asked Questions
What is the Heat Shrink Double Layer Tube used for?
It is used for:
- Insulating and outer-shielding layer in power cable straight-through joints up to 36 kV
- Any application requiring combined insulation and shielding
How do I choose the right size?
A heat-shrink part is chosen by two diameters. As supplied (D min. (mm)) it must open wider than the largest thing it has to slide over; after shrinking (d max. (mm)) it must close smaller than the smallest thing it has to grip. Measure both on your cable or busbar and pick the first code in the selection chart that satisfies both.
How is it installed?
Clean and degrease the surface, position the part, then shrink it with a gas torch or a hot-air gun: keep the heat moving round it with a smooth, brushing motion so it recovers evenly without scorching. Start at one end and work steadily along to the other.
Which standards and test methods are quoted for it?
These, with the values in the Technical Specification on this page:
- ASTM D638
- ASTM D2671
- ASTM D2240
- ASTM D570
- ASTM D149
- ASTM D257
- ESI 09-11
- IEC 216
Where can I download the datasheet?
From the "Download datasheet" button at the top of this page, or here:
Can I get a quote, a sample or a size that is not listed?
Send your cable details, quantity and application with the "Request a Quote or Sample" form at the foot of this page. For a size or variant that is not in the chart, describe what you need there, or use Technical support at the top of the page, and the technical team will confirm what can be supplied.
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