Cable End Caps | Cable Pulling & Storage | Part 2
Published 26 Oct 2021
Cable Pulling & Storage – Part 2
Stephen Harrison – Training & Technical Manager at Current Training Service Pty Ltd
I found when I have pulled cables, the pulling sock can damage the end cap causing water to penetrate the cable. Water is one of the most destructive elements and introducing it to a piece of cable can reduce the cables service life. The biggest cause of water in cables, is storage or pulling the cable in through pits, ducts, or open trench incorrectly capped.
When pulling cables with a pulling sock, the use of a triple end seal is a safe option. The triple end seal consists of two end caps, mastic and a heatshrink tube. It is a simple kit which helps resist the cable from getting water ingress around the pulling sock area.
Abrade the cable first and remove dirt or mud allowing for the mastic and first end cap to seal onto the cable. Mastic is applied at pre-determined length, and a piece of medium wall tubing is shrunk down over the end cap and mastic onto the cable. This piece of heatshrink is around 200-240mm long and is the strength of this kit.
More mastic is applied, with the last end cap installed over the medium wall heatshrink and inner end cap completing the triple end seal. Caution must be observed, do not pull the cable until the heatshrink has cooled.
Why So Many Components?
The top end cap is sacrificial and might be damaged by the pulling sock or other pulling gear, but the inside end cap is not disturbed.
The inside cap is sealed to the cable and will not get damaged when the cable is under tension whilst being installed. The medium wall tubing and mastic help with mechanical strength for the inner end cap, preventing the pulling sock from biting into the inner end cap or pulling the external end cap off whilst sealing the cable.
The triple end seal is also good for cables which require storage underground or in pits until they are ready for joining or terminating. As there are mastic seals in the kit, these create a water seal on the cables. I have personally seen triple end seals on cables in water up to 3 meters deep, and they have not leaked water.
At every cable pull and storage installation, stop and ask, have the cable ends been sealed correctly? Which kit should I use for the application?
Part 3 will explain about water getting into cables whilst drums of cable are outside not capped correctly.
➡ Read Part 1 here Cable Pulling & Laying | Sealing Cables Whilst Installing | Part 1