Cable tools

CPT stands for “Cable Preparation Tool”.

An CPT is a tool dedicated to working on the cable to prepare it, strip it, ... as required.

The use of tools dedicated to cable preparation on transmission and distribution electricity networks provides two essential advantages that contribute to the efficiency of an electrical network :

• Operator safety : During cable preparation (for example, when removing the sheath), the operator may need to exert significant force with a sharp tool to remove it. It is in this precise case that many accidents occur, resulting in lifelong injuries. Dedicated tools allow these demanding stripping operations to be carried out safely.
• Network reliability : For cable preparation before the installation of joints or terminations, if we take the example of synthetic underground distribution cables, the following main operations must be performed :
  • Sheath removal
  • Semi-conductor removal
  • Insulation removal

For each of these steps, strict adherence to the dimensions specified in the accessory's manual and ensuring that the layer beneath the one being worked on is not damaged will have a direct impact on the accessory's lifespan and, consequently, the network’s efficiency.

Given that semi-conductor thicknesses range between 0.4 mm and 1.5 mm, and that a single scratch on the insulation (located under the semi-conductor) would drastically reduce the accessory's lifespan, this presents a significant challenge that requires appropriate equipment, rather than a knife, for example.

With the exception of low-voltage cable preparation tools used for live-line work, which are designed to protect operators from electrical hazards and must comply with the IEC 60900 standard, there is no international standard dedicated to cable preparation tools.

More than a specific time, it would be better to provide an idea of the total length of material that can be removed or stripped.

In reality, depending on the layer of material, two main factors will affect the blade's lifespan :

First, the proper adjustment of the tool : for instance, during insulation stripping, if the blade grazes or even directly contacts the conductor, the cutting quality of the blade will be immediately affected, and replacement will become more urgent to maintain optimal work quality.

Second, the different materials used for the various layers of cables worldwide make it impossible to predict the blade's lifespan. For example, in the case of removing a non-strippable semiconductor located on the insulation, some materials are much more abrasive than others, and blade dulling can occur three times faster depending on the material.

Therefore, the operator must always keep a close eye on the result obtained after cable preparation to determine whether a blade change or sharpening is necessary.

There is no need to recommend a new tool; you just need to call us and provide the reference of your tool (or send us a photo) so that our sales team can send you a quote to replace the lost handle.

What should I do if my tool damages the cable ?

Several reasons can cause an unwanted mark on the cable.

It is advisable to check the following points :

• Does the tool correspond to the cable and the required function ?
• Is the blade properly adjusted ?
• Has any other blade or part not been removed ?
• Are the cable and the tool clean ?
• Is the tool or blade not too worn ?

If you still cannot find the cause after all these checks, call our technical service for assistance.

In synthetic underground distribution cables (HTA/Medium voltage), there is a layer called “external semiconductor,” which is found on the cable's insulation.

Depending on the process used during the manufacture of these cables, it is possible to operate in two ways :

• Double extrusion : internal semiconductor + insulation
• Triple extrusion : internal semiconductor + insulation + external semiconductor

The external semiconductor will be strippable in the first case and non-strippable in the second.

In the first case, when the cable is referred to as “strippable,” the external semiconductor can be presented like a banana peel. To remove it during the preparation of a cable for a joint or termination, the external semiconductor can be incised and, only afterward, peeled off from the insulation, just like peeling a banana.

In the second case, when the cable is referred to as “non-strippable,” the external semiconductor can be presented like an apple peel. To remove it, the external semiconductor can thus be “peeled” like the skin of an apple.

There are several risks when incising a cable, but two major risks stand out :

• Making an incision too deep : this will create scratches or even "cuts" on the insulation, thus creating significant points of electrical stress, which will inevitably drastically reduce the lifespan of the joint or termination.
• Making an incision too shallow : in this case, something as simple as peeling a ripe banana will turn into a tedious task, with the semiconductor tearing in random places. It will then be necessary to constantly peel off bits of semiconductor left stuck to the cable.

Once again, there are two main risks when peeling a cable :

• Just like peeling an apple, if the insulation is peeled too deeply, too much of the “fruit” will be removed. In the case of an underground cable, too much primary insulation will be removed, leaving the insulation with an electrical risk potential.
• On the other hand, if the peeling is not deep enough, some of the semiconductor will remain on the insulation. This will then need to be removed afterward, extending the preparation time and increasing the risk of altering the nearly perfectly cylindrical shape of the insulation.

Even if you choose the best cable and the best accessory for your underground distribution network, if the cable preparation is not perfect, the optimal efficiency of your network will never be reached.

At Penta, we offer a range of tools dedicated to cable preparation, which will save you time when precision is important and your safety is at stake.

This is a typical case where, if the classic recommended method is followed, there is a risk of causing even more damage to the insulation. Indeed, each time the semiconductor breaks, it is necessary to catch a small piece of it to peel off the rest of the incised semiconductor. By doing so, the user increases the chances of creating alterations to the perfectly smooth surface of the insulation, creating several electrical stress points.

The operator can either continue down this path, accepting the risks, or opt for two other methods that have been observed in the field :

Restoring elasticity to the semiconductor : so that it stops breaking during its removal after incision. To do this, the operator has two solutions, frequently observed and varying depending on the environment, operator permits, and practices recommended or imposed by the utility company :

• Using a torch
• Using a heat gun

Removing the peelable semiconductor while cold, but in the same way as a non-peelable semiconductor : in this case, the user must be particularly careful to keep the removed insulation thickness to a strict minimum throughout the stripping process.