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Alroc Cable Jointing Tools Explained

Published 22 Jul 2026

Specialist cable jointing tools used to prepare MVHV power cables before installing joints, terminations and connectors.

Alroc cable jointing tools are specialist cable preparation tools used by cable jointers to strip, cut, remove, chamfer and prepare LV, MV, HV and EHV power cables before installing cable joints, terminations and connectors.

In medium and high voltage cable systems, preparation accuracy is critical. Before an 11kV, 33kV, 66kV or 132kV cable can be jointed or terminated, the cable layers must be removed to the correct dimensions without damaging the insulation, conductor, semi-conductive screen, metallic screen or outer sheath.

Alroc tools are used for tasks such as outer sheath removal, bonded semi-con screen removal, peelable semi-con screen removal, XLPE insulation stripping, cable chamfering, grooving and general cable preparation. These are specialist tools designed for professional cable jointers working on power distribution, utilities, substations, renewables, industrial networks and high voltage cable systems.

Thorne & Derrick supply Alroc cable jointing tools together with MV HV cable jointing tools, cable stripping tools, semi-con removal tools, cable insulation stripping tools and cable preparation equipment for LV, MV, HV and EHV cable installations.

Quick Answer: What Are Alroc Tools?

Alroc tools are specialist cable preparation tools used by cable jointers to prepare LV, MV, HV and EHV power cables before jointing or termination. They are used to remove outer sheaths, semi-conductive screens, insulation and other cable layers accurately and safely.

Alroc cable jointing tools are commonly used on 11kV, 33kV, 66kV and 132kV cable systems, including XLPE and EPR insulated cables. They help jointers achieve accurate cutbacks, clean stripping, controlled cutting depths and repeatable cable preparation before installing cable joints, terminations or connectors.

Alroc Cable Jointing Tools: Quick Summary

What They Are Specialist cable preparation tools used before installing cable joints, terminations and connectors.
Used By Cable jointers, utilities, DNOs, contractors, substations, rail, renewables and industrial power teams.
Typical Cable Layers Outer sheath, semi-conductive screen, XLPE insulation, EPR insulation, metallic screen and conductor preparation areas.
Common Voltage Levels LV, 11kV, 33kV, 66kV, 132kV and selected EHV cable applications.
Main Benefit Accurate, repeatable cable preparation that helps reduce the risk of damage before jointing or termination.

What Are Alroc Cable Jointing Tools?

Alroc cable jointing tools are precision cable preparation tools designed for the controlled removal of cable layers. They are used before installing medium and high voltage accessories such as heat shrink joints, cold shrink joints, cable terminations, separable connectors, plug-in connectors and sealing ends.

In a typical MV or HV cable preparation process, the jointer may need to:

  • Remove the outer cable sheath
  • Prepare the metallic screen or shield
  • Remove bonded or peelable semi-conductive screen
  • Strip XLPE or EPR insulation
  • Chamfer the insulation or semi-con cutback
  • Prepare the conductor for connector installation
  • Create accurate dimensions for the joint or termination kit

The aim is to prepare the cable exactly as required by the accessory manufacturer’s installation instructions. Incorrect cutback dimensions or damaged insulation can affect the reliability of the completed joint or termination.

View the full Alroc cable tooling range available from Thorne & Derrick.

Why Are Alroc Tools Used?

Alroc tools are used because cable preparation is one of the most important stages in MV and HV jointing. A cable can pass all factory tests but still fail later if it is damaged during installation or poorly prepared before jointing.

Specialist tools help cable jointers achieve:

  • Controlled cutting depth to avoid damaging underlying cable layers.
  • Clean cutbacks for joints, terminations and connectors.
  • Repeatable preparation across multiple cables and phases.
  • Accurate stripping dimensions in line with kit instructions.
  • Reduced risk of knife damage compared with manual stripping methods.
  • Improved finish quality on semi-con and insulation preparation.
  • Safer working by using the correct tool for the cable layer.

The higher the voltage, the more critical preparation quality becomes. On MV and HV cable systems, small cuts, scratches, steps, voids or contamination around the insulation and semi-con screen can create long-term electrical stress points.

Cable Layers That Need Preparation

MV and HV cables are built from several layers. Each layer has a specific role, and each must be prepared correctly before jointing or termination.

MV HV Cable Layers Prepared By Jointing Tools

Outer Sheath The external protective jacket that must be removed to access the cable screen, armour or underlying layers.
Metallic Screen Copper wires, tapes, lead sheath, aluminium screen or other metallic layers used for screening, fault current and earthing functions.
Semi-Conductive Screen A black semi-conductive layer over the insulation that must be removed accurately before jointing or termination.
Insulation The main cable insulation, commonly XLPE or EPR, which must be stripped and chamfered carefully without defects.
Conductor The current-carrying core, prepared for connector, lug or ferrule installation depending on the cable accessory.

For more technical background, see the Power & Cables guide to the screen semi-conductive layer on MV cables.

Types Of Alroc Cable Tools

Alroc manufactures a wide range of cable preparation tools. The correct tool depends on the cable layer being removed, the cable diameter, the insulation type and the accessory being installed.

Common Alroc Cable Tool Types

Outer Sheath Removal Tools Used to strip or remove the outer jacket from armoured and unarmoured power cables.
Semi-Con Screen Removal Tools Used to remove bonded, semi-bonded or peelable semi-conductive screens from MV and HV cables.
Insulation Stripping Tools Used to remove XLPE, EPR, PVC or PE cable insulation to the required dimensions.
Multi-Function Tools Used for combined preparation tasks such as cutting, stripping, grooving or chamfering.
HV/EHV Preparation Tools Used for larger transmission cable preparation, including high voltage and extra high voltage cable systems.

Browse Alroc tools for cable jointing, termination and preparation.

Semi-Con Screen Removal Tools

The semi-conductive screen is one of the most critical cable layers to prepare correctly. It sits over the cable insulation and helps provide a smooth electrical field between the insulation and metallic screen.

When installing a joint or termination, the semi-con screen must be removed cleanly to the correct cutback length. If it is removed poorly, the cable may be left with scratches, steps, contamination or uneven edges that can create stress points.

Alroc semi-con screen removal tools are used for:

  • Bonded semi-con screen removal
  • Peelable semi-con screen removal
  • Semi-bonded screen preparation
  • Cold strippable screen preparation
  • Chamfering the semi-con cutback where required

A common example is the Alroc CWB18-60 tool family, used for bonded semi-con screen stripping on MV and HV cables. The exact tool variant must always be matched to the cable type, diameter and screen construction.

View semi-con screen removal tools for MV and HV cable preparation.

Outer Sheath Removal Tools

The outer sheath is the external protective jacket of the cable. It protects the cable during handling, pulling, burial, installation and service. Before jointing or termination, part of the outer sheath must be removed to expose the underlying screen, armour or cable construction.

Outer sheath preparation must be controlled carefully. Cutting too deeply can damage metallic screens, lead sheaths, aluminium screens or other underlying layers. Cutting too shallowly can make the sheath difficult to remove and slow down preparation.

Alroc outer sheath removal tools are used for:

  • Circular cutting around the cable
  • Longitudinal cutting along the cable sheath
  • Controlled depth cutting
  • Preparation of armoured and unarmoured cables
  • Preparation of LV, MV, HV and EHV cable sheaths

View outer sheath removal tools for cable jointing and termination work.

Cable Insulation Stripping Tools

After the outer layers and screens are prepared, the cable insulation may need to be stripped to expose the conductor for connector installation.

On MV and HV cables, the insulation layer is not simply removed with a knife. It must be stripped cleanly and accurately to avoid leaving grooves, cuts, scratches or uneven surfaces. The insulation may also need to be chamfered or pencilled depending on the accessory design.

Alroc insulation stripping tools are used for:

  • XLPE insulation removal
  • EPR insulation removal
  • Controlled insulation cutback
  • Insulation chamfering
  • Preparing cables before installing connectors, lugs or ferrules

For example, tools in the Alroc LH range are commonly associated with insulation stripping and cable preparation before installing joints, terminations or connectors.

View cable insulation removal tools.

Alroc Tools For MV & HV Cables

Alroc tools are widely used for medium and high voltage cable preparation, especially on 11kV and 33kV power cables. Selected tools are also used for 66kV, 132kV and EHV cable preparation depending on the cable construction and tool range.

Alroc Tools By Cable Voltage

LV Cables Used for selected sheath stripping and cable preparation tasks where specialist tooling improves accuracy and safety.
11kV & 33kV Cables Commonly used for outer sheath removal, semi-con screen removal, XLPE insulation stripping and preparation before MV joints and terminations.
66kV & 132kV Cables Used for specialist HV cable preparation where cable diameter, sheath type, screen construction and accessory instructions require dedicated tooling.
EHV Cables Used for selected transmission cable preparation applications where larger diameter and higher precision tooling is required.

For wider tooling options, see cable and installation tooling for LV, MV and HV power cables.

How To Select Alroc Tools

Selecting the correct Alroc cable tool depends on the cable and the task. The wrong tool can damage the cable or create a preparation profile that does not match the joint or termination kit.

Alroc Tool Selection Checklist

Cable Voltage Confirm whether the cable is LV, 11kV, 33kV, 66kV, 132kV or EHV.
Cable Diameter Check the diameter over the layer being stripped, not only the overall cable diameter.
Cable Insulation Identify whether the cable is XLPE, EPR, PVC, PE or another insulation type.
Semi-Con Type Confirm whether the semi-con screen is bonded, semi-bonded, peelable or cold strippable.
Cable Layer Select the tool for the exact layer being prepared, such as outer sheath, semi-con screen or insulation.
Accessory Instructions Check the joint, termination or connector installation instructions for cutback lengths and preparation requirements.
Jointer Competence Ensure the tool is used by trained and competent personnel familiar with MV and HV cable preparation.

The tool should always be selected using accurate cable data, not assumptions from voltage level alone.

Common Cable Preparation Mistakes

Cable preparation problems can directly affect the long-term reliability of cable joints and terminations.

Common mistakes include:

  • Using a knife instead of a specialist tool – manual cutting increases the risk of scoring insulation or damaging underlying layers.
  • Selecting the wrong tool diameter range – the tool must match the diameter over the layer being prepared.
  • Confusing bonded and peelable semi-con screens – different screen types may require different tools and preparation methods.
  • Cutting too deeply – overcutting can damage insulation, metallic screens, lead sheaths or aluminium layers.
  • Leaving an uneven semi-con cutback – poor edges can create electrical stress points.
  • Not chamfering where required – some accessory designs require a specific chamfer or transition profile.
  • Ignoring accessory instructions – cutback dimensions should follow the joint or termination manufacturer’s instructions.
  • Poor tool maintenance – blunt blades, worn parts or incorrect settings can reduce preparation quality.
  • Contaminating the prepared insulation – cleanliness is critical before installing MV and HV accessories.

For MV and HV work, cable preparation should be treated as a controlled technical process, not a basic stripping task.

Alroc tools sit within the wider cable jointing and cable preparation tooling range.

Alroc Cable Jointing Tools FAQs

Q: What are Alroc tools used for?

A: Alroc tools are used by cable jointers to prepare LV, MV, HV and EHV cables before installing joints, terminations and connectors. They are commonly used for outer sheath removal, semi-con screen removal, insulation stripping and cable chamfering.

Q: Are Alroc tools used on 11kV and 33kV cables?

A: Yes. Alroc tools are widely used for 11kV and 33kV cable preparation, including semi-con screen removal, outer sheath stripping and XLPE insulation preparation before jointing or termination.

Q: What is a semi-con screen removal tool?

A: A semi-con screen removal tool is used to remove the black semi-conductive screen from MV or HV cable insulation. The screen must be removed cleanly and accurately before installing joints, terminations or connectors.

Q: Why is cable preparation so important?

A: Cable preparation is important because damage to the insulation, semi-con screen, sheath or conductor can affect the reliability of the completed joint or termination. Accurate preparation helps reduce the risk of electrical stress, partial discharge and future cable faults.

Q: Can one Alroc tool prepare every cable layer?

A: No. Different cable layers usually require different tools. Outer sheath removal, semi-con screen removal and insulation stripping are separate preparation tasks, and the correct tool depends on the cable type, diameter and layer being removed.

Q: What information is needed to select an Alroc tool?

A: To select an Alroc tool, you need the cable voltage, cable construction, diameter over the layer being stripped, insulation type, semi-con type, accessory instructions and the specific preparation task being carried out.

Q: Are Alroc tools only for high voltage cables?

A: Alroc tools are commonly associated with MV and HV cable preparation, but selected tools can also be used for LV and EHV cable applications depending on the tool type, cable construction and required preparation task.

Q: What happens if the semi-con screen is removed badly?

A: Poor semi-con screen removal can leave scratches, steps, contamination or uneven cutbacks on the cable insulation. These defects can create electrical stress points and may affect the long-term performance of the joint or termination.

Conclusion

Alroc cable jointing tools are specialist tools used to prepare LV, MV, HV and EHV power cables before installing cable joints, terminations and connectors. They help cable jointers remove outer sheaths, semi-conductive screens and insulation accurately, safely and repeatably.

Correct cable preparation is critical to the reliability of MV and HV cable systems. The right tool must be selected according to the cable voltage, diameter, insulation type, semi-con screen type, cable construction and accessory installation instructions.

Thorne & Derrick supply Alroc cable tools, cable jointing tools, semi-con screen removal tools, outer sheath stripping tools, insulation stripping tools and multi-function cable preparation tools for LV, MV, HV and EHV cable installations.