Double Layer Heat Shrink Tube - Insulating and Semi-Conductive (GDLT)

About Double Layer Heat Shrink Tube - Insulating and Semi-Conductive (GDLT)

Building the insulation of a heat-shrink cable joint normally takes an insulating tube followed by a separate semi-conductive tube for the outer screen. Gala's Double Layer Tube (GDLT) combines the two. Its two layers are co-extruded together: a red heat-shrinkable insulating layer on the inside and a black heat-shrinkable semi-conductive layer on the outside. One shrinking operation lays down both, saving a step in the joint.

GDLT is used mainly as the insulating and outer-screening layer of power cable straight-through joints on systems up to 33 kV (36 kV equipment), and wherever insulation and a screen are needed together. In Gala's own joint kits it is fitted over the shrunk insulating tube.

Eight sizes run from GDLT 30/11 to GDLT 120/45. Recovered wall thickness is 5.0 mm for the sizes up to 65/27 and 7.0 to 7.5 mm for the larger sizes. The first figure is the minimum inside diameter as supplied, the second the maximum inside diameter after recovery.

The tube starts to shrink at about 100 deg C and recovers fully at 130 to 135 deg C; it is rated for continuous use from -40 deg C to +100 deg C.

Manufactured by Gala in India. Datasheet and size selection on request.

Specifications

• Brand: Gala
• Product type: Co-extruded double layer heat shrink tube (insulating inner, semi-conductive outer)
• Material: Cross-linked polyolefin, two co-extruded layers
• Colour: Red inner layer, black outer layer
• Voltage rating: For cable joints on systems up to 33 kV (36 kV equipment)
• Operating temperature: -40 deg C to +100 deg C continuous
• Size range: 30 mm to 120 mm supplied ID; 11 mm to 45 mm recovered ID
• Wall type / thickness: 5.0 mm (30/11 to 65/27), 7.0 to 7.5 mm (85/30 to 120/45) after recovery
• Standards tested to: Test methods quoted on Gala's datasheet - ASTM D638, ASTM D2671, ASTM D2240, ASTM D570, ASTM D149, ASTM D257
• Application: Insulating and outer-screen layer of power cable straight-through joints
• Installation: Heat-shrunk with a gas torch as part of the joint build-up
• Country of origin: India
• Shrink temperature: Starts at 100 deg C; full shrink 130 to 135 deg C
• Insulating layer - tensile strength: 12 MPa min (ASTM D638)
• Insulating layer - elongation at break: 300% min
• Insulating layer - hardness: 50 +/- 3 Shore D
• Insulating layer - water absorption: 0.5% max
• Insulating layer - thermal ageing: after 120 deg C for 500 h, tensile 10.5 MPa min and elongation 270% min

Sizes

• GDLT 30/11 | D 30 / d 11 | T 5.0 +/- 0.3
• GDLT 35/13 | D 35 / d 13 | T 5.0 +/- 0.3
• GDLT 45/16 | D 45 / d 16 | T 5.0 +/- 0.3
• GDLT 55/20 | D 55 / d 20 | T 5.0 +/- 0.3
• GDLT 65/27 | D 65 / d 27 | T 5.0 +/- 0.3
• GDLT 85/30 | D 85 / d 30 | T 7.5 +/- 0.3
• GDLT 100/35 | D 100 / d 35 | T 7.0 +/- 0.3
• GDLT 120/45 | D 120 / d 45 | T 7.0 +/- 0.4

Applications: Cable joint kit makers, cable jointing contractors, power distribution utilities, cable manufacturers, industrial and infrastructure MV networks