Buried — a cable end going into duct

Sealing a duct-bound end and pulling on it at once

Five codes, GEC 301L-PE to GEC 701L-PE, taking 28 to 112 mm of cable at a published minimum pulling strength of 150 to 450 kg.

Match the cable diameter to a code

Where this end is going

This end is going buried. It crosses the rollers in air and then lies in a duct that may stand in water for the rest of its service life, and it has to be closed before the draw begins, because once the cable is in the duct nobody can reach the end again. A heat-shrink end cap with an eye set into its closed face does both jobs in one movement: it shuts the end, and it is what the winch rope shackles to.

The eye is anchored in the cap, and the cap recovers down onto the jacket rather than gripping the conductor. The pull is therefore taken by the whole cable, jacket and conductor together, instead of by the conductor alone. That is a deformation argument before it is a strength one: spreading the load over the full section keeps the cable from being drawn out of shape on a long or tight run. The manufacturer publishes a minimum pulling force of 13 N/mm² for the range and a minimum pulling strength code by code, from 150 kg (330 lb) to 450 kg (990 lb).

One part, two jobs, so nothing is fitted in sequence: no pulling sock stocked against a cable size, no crimper carried out to the drum, no separate cap to fit once the sock comes off. Recovered properly the cap is very hard to pull off, and it closes the end against water and moisture ingress. That is a seal made on the jacket by the cap itself, not a cover slipped over the end. The IP68 class belongs to the Insulcap sealing caps; the published data for this variant claims sealing without an IP class, and this page will not borrow one across.

Fitting is normally done at the works before the drum ships, which puts it inside the same decision as closing an end at despatch. It can also be fitted in the field with a gas torch, propane preferred over butane; the torch procedure is written once on this site and not repeated here. The published range carries no push-on or cold-shrink equivalent of this part, so where a hot-work permit will not be granted the choice changes shape: see closing an end where a torch is not allowed.

Heat-shrink end cap with cable pulling eye — GEC 301L-PE to GEC 701L-PE

The pulling eye is built into the closed face, so the component that seals the end is the component the winch loads. Five codes cover cable from 28 to 112 mm outside diameter.

Seal and pulling connection in one component — no sock, no crimper, no special tool
Load carried by jacket and conductor together, so the cable deforms less during the draw
Sealed against water and moisture ingress once recovered
Fitted at the works or on site with a gas torch

Codes	GEC 301L-PE, 401L-PE, 501L-PE, 601L-PE, 701L-PE
Cable range	28 to 112 mm (1.1 to 4.4 in)
Minimum pulling strength	150 to 450 kg (330 to 990 lb), by code
Minimum pulling force	13 N/mm²
Tf, ±10%	3.5 to 4.6 mm
Shrink temperature	125 °C
Continuous temperature limit	−40 to +100 °C
Dielectric strength	12 kV/mm minimum
Fitting	Factory fitted as standard; field fitted with a propane or butane torch
Cable types	Power and telephone cable

ASTM D638ASTM D792ASTM D2240ASTM D570ASTM D2671ESI 09-11IEC 216ASTM D149ASTM D257ASTM D150

Manufacturer datasheet (PDF)

Selection chart

Code No.	Ds min.	Df max.	Ls min.	Tf ±10%	Pulling strength min.	Cable range
GEC 301L-PE	55	25	170	3.5	150 kg	28 – 38
GEC 401L-PE	75	35	180	4.0	250 kg	38 – 52
GEC 501L-PE	100	45	200	4.0	300 kg	50 – 70
GEC 601L-PE	130	65	300	4.6	400 kg	65 – 91
GEC 701L-PE	160	65	300	4.5	450 kg	80 – 112

D is an internal diameter; s is as supplied, f is after free recovery. The manufacturer's key decodes D, s and f only, so T and L are reproduced here as published and not decoded. Dimensions in millimetres.

Physical properties

Property	Value	Test method
Tensile strength	12 N/mm² (min.)	ASTM D638
Ultimate elongation	350 % (min.)	ASTM D638
Density	1.05 ± 0.2 g/cm³	ASTM D792
Hardness	45 ± 10 Shore D	ASTM D2240
Water absorption	0.2 % (max.)	ASTM D570

Thermal properties

Property	Value	Test method
Accelerated ageing	120 °C for 500 hrs	ASTM D2671
Tensile strength	11 N/mm² (min.)	ASTM D638
Ultimate elongation	300 % (min.)	ASTM D638
Low temperature flexibility, −40 °C for 4 hrs	No cracking	ASTM D2671
Heat shock, 250 °C for 30 min	No cracking or flowing	ESI 09-11
Shrink temperature	125 °C	IEC 216
Continuous temperature limit	−40 to +100 °C	IEC 216

The tensile and elongation rows below the ageing row are the values retained after that exposure.

Electrical properties

Property	Value	Test method
Dielectric strength	12 kV/mm (min.)	ASTM D149
Volume resistivity	1 × 10¹⁴ Ohm.cm (min.)	ASTM D257
Dielectric constant	5 (max.)	ASTM D150

What each of these rows is actually evidence of is set out on what an end-cap datasheet proves.

What this part will not do for you

Five limits worth knowing before the code goes onto a purchase line.

It does not raise the cable's own pulling limit. The 150 to 450 kg is the strength of the cap; the cable maker's maximum tension is a separate figure, and the draw is governed by whichever is lower, usually not the cap.
One figure per code, for a straight pull. Nothing is published for side load at a bend, for a roller, or for torsion in the rope, so the swivel stays the installer's call.
The chart stops at 112 mm. Above GEC 701L-PE this range has nothing, and a larger end must be closed and pulled by other means.
It is not an energised-end part. A live end wants the construction on live end caps, each core capped separately under an outer cap.
It has no relief valve. A sealed HV end standing in a hot yard builds gas behind the cap, which is the argument for the de-gassing variant.

Questions this page gets asked

Do I still need a pulling sock?

Not within the sizes this chart covers: the cap is the pulling connection. You do still need the cable maker's maximum tension, because that number and this one are different limits and only the lower is real.

What is the 13 N/mm² figure for?

It is published as the minimum pulling force for the range, as a stress. It is not the tensile strength row above, which reads 12 N/mm² minimum and carries a named test method. Specify against the per-code kilogramme figures, not against either stress number.

Which code takes a 63 mm cable?

GEC 501L-PE, cable range 50 to 70 mm, minimum pulling strength 300 kg (660 lb). Overlaps matter: a 65 mm cable falls inside both 501L-PE and 601L-PE, and those codes are 100 kg apart on pull, so check the size chart before quoting.

Is it rated IP68?

The published data for this variant states sealing against water and moisture ingress and gives no IP class; IP68 belongs to the Insulcap caps. If your specification needs an IP number written against it, take it from the part that carries one.

Can it be fitted after the cable is on the rollers?

Physically yes, with a torch, and that is what the field-fitted route is for. In practice the end wants closing at the works: a cap recovered beside a duct mouth is being recovered in the worst conditions the job offers, which is where most of why end seals fail begins.

Where to go next

Send the cable diameter and the pull

A cable outside diameter in millimetres, the run length and the tension the cable maker allows are enough to come back with a code rather than a question. Open End publishes and does not manufacture; the parts are made by Gala Thermo Shrink Pvt. Ltd. of Mumbai.

Contact Read the size chart first