Insulated Tools & Live Cable Jointing

Published 19 Dec 2017

Insulated Tools

Ad: Insulated Tools (Live Line & Cable Jointing Tool Sets) – T&D supply a full range of insulated tools kits for electrical engineers, cable jointers and overhead linesmen

Boddingtons Electricals - Cable Jointing Tools

Electrical Safety & Live Working Equipment

  • uploaded by Chris Dodds - Thorne & Derrick 

In the UK the Distribution Network Operators permit appropriately accredited ICP’s to carry out live cable jointing onto service and mains connections on their low voltage electrical distribution systems – those cable jointers must be trained, assessed and authorised as competent to work on live cables with a professional working knowledge (practical and theoretical) of the electrical safety considerations when jointing energised cables.

Furthermore, contractors must use approved and tested insulated tools, jointing tools and electrical safety equipment to prevent workplace risk becoming workplace accident.

Insulated tools will protect workers against contact with live circuits and cables. Without them you could be risking serious injury, liability or even death.

Typical 400v low voltage cables jointed under live conditions are waveform, wavecon, PILC STA and Consac – live working is essential but not encouraged and suitable arc flash clothing should be worn when carrying out maintenance on energised substations, cables and electrical equipment. See the UK HSE HSG85 document for further information about safe working near dead or live electrical equipment.

The following series of site photographs kindly contributed by Billy Ayling, an authorised Live Cable Jointer, shows the stages of cable stripping, preparation, shrouding and branch jointing of wavecon cables. The photo’s were taken by the Jointers mate.

  • Application: Live Cable Jointing
  • Cable Joint Type: Breech/Branch Joint
  • Cable Type: Wavecon Cables – 95sqmm 3 Core Wavecon Breeched 
  • Cable Jointer: Billy Ayling (Self Employed – DNO (SSE) Trained Live LV / 11kV Jointer

About Billy,

Billy has worked in the utility industry since leaving school in 2001 and has been a cable jointer since 2010. Professionally trained at SSE Thatcham Jointing School and authorised to fault find, repair and cable joint wavecon, consac, PILC SWA and associated services with additional skills including operating and linking on the low voltage electricity network.

Cable Jointing In The Danger Zone 

With nerves of steel and the concentration powers of a chess Grandmaster a live cable jointer must maintain a steady hand and focussed mind when working on live cables.

Billy comments, “the main risk during live cable jointing is losing concentration – generally I would not speak to my Jointers mate whilst live working on cables unless something critical to the cable joint installation is required. All adjacent conductive metal work must be shrouded using rubber insulating shrouds UV stabilised suitable for outdoor and underground use in cable trenches. Only one phase should be worked on at a time.”

Typically, when working on Live LV Conductors insulating gloves should be used when working on, or in close proximity to cables – UK DNO’s such as Scottish Power Energy Networks (SPEN) according to their policy guideline Rubber Gloves For Electrical Purposes recommend jointers wear Class 1 insulated gloves (7.5kV) to the British Standard BS EN 60903 (2003).

Hand protection is vital as is the use of dielectric boots where there is a real risk to the cable jointer of electrical shock from either low voltage or high voltages – see insulating boots for further information on suitable PPE for jointers.

An 11kV Jointer 

Billy has ascended the voltages and is currently a high voltage cable jointer authorised to work on 11kV polymeric (XLPE) and 11kV paper (PILC PICAS) insulated cables.

Insulated Tools

1 View From The Trenches – working conditions complicate but do not prevent skilled cable jointers from live working in cramped and confined underground cable trenches. Here, the cable fault has been located and the damaged cable excavated prior to jointing. In the field, jointer training centre conditions are never replicated with an onus on the jointer to maintain high skill levels, concentration and dexterity in the face of bad weather and under pressure to restore power to our homes or businesses with minimum disruption.

Insulated Tools

2 – Mud, Mud, Glorious Mud – plodging in muddy holes with conditions favoured by hippo’s the cable jointer must maintain complete awareness of the electrical safety precautions and considerations required for safe live working on LV cables. The centre of the wave is accurately located on the cable – this must be done to ensure correct cable stripping and separation of the copper neutral earth wires. Also, the waveform cable is marked up for where to strip the cable prior to jointing.

Insulated Tools

3 Get Stripped! – the cables are carefully prepared using jointers tools to remove the cable sheath and expose the cable and conductors to allow the cable joint to be installed. Here, the jointer has relied on insulated cable knives to safely remove the waveform cable sheath. Correct cable preparation is essential to avoid malfunction of the cable joint post-energisation.

Insulated Tools

4 Shocking Risks – the cable jointer uses insulated tools to work on the live cables to avoid potential electrocution when live working. The jointer uses insulated cable wedges to space cores for testing (hence the lamps) and provide space for the ‘w’ breech connectors. Insulated tool kits would usually include insulated pliers, cable cutters, sockets, spanners, wrenches and screwdrivers – contact us for further information.

Insulated Tools

5 Shrouded For Safety – the jointer uses Boddingtons rubber insulating shrouding to protect against live voltages up to 1000V when underground cable jointing. Insulated clamps hold the protective shrouding in position covering the live cables so the LV cable joint can be positioned and installed.

Insulated Tools

6 Insulated Tools – the jointer has used an insulated ratchet tool to tighten the shear off bolts on the mechanical shearbolt connectors. Insulated wedges to were used to separate the cable cores and an insulated knife used to strip insulation from the cores. Cable joint is manufactured by TE Connectivity and approved by SSE – this is a completed wavecon to wavecon 95sqmm 3 core mains breech joint.

Insulated Tools

7 Hometime – the branch joint is completed with the shell encapsulating the jointing resin and ready for trench backfilling. Live cable jointing should only ever be carried out by competent and certified Jointers using the correct jointing, insulated tools and electrical safety equipment.

Live Cable Joints

SSE Scottish & Southern Energy – a live low voltage 185sqmm wavecon straight joint prior to filling the joint shell with cable joint resin.

Cable Joints - The Birdcage

Cable Joints – The Birdcage. Here, the cable jointer ensures the binders are cut off before cable joint is ‘complete’ making a cage around the crutch rather than just split apart as per the previous photo. Although forming part of the SSE jointers trade test at the Jointing School this is rarely used in the field. The neutral earths are formed as a “bird-cage” type arrangement at the cable crotch using wire binders. Image: Lee Richards (LV 33kV Competent Cable Jointer).


Insulated Tools & IEC 60900

IEC 60900 Insulated Tools

IEC 60900 Symbol

Quality insulated tools should be tested to IEC 60900 – this standard controls hand tools for live working up to 1000 V a.c. and 1500 V d.c.

Look for the official 1000V symbol, this will ensure the tools protect workers against accidental or incidental contact with electricity voltages up to 1000V. Purchase a copy of IEC 60900 from the IEC webstore here.

T&D also distribute the complete range of Class 0, 1, 2, 3 and 4 ranges of insulating matting to provide protection to utility workers, substation workers and cable jointers working on low, medium and high voltage cables and power systems.

Thorne & Derrick
Specialist Electrical DistributorThorne & Derrick

LV ♦ MV ♦ HV

T&D distribute the most extensive range of LV, MV & HV Cable Joints & Terminations for repairing, jointing and connecting 11kV/33kV cables in underground cable trenches or substations, switchgear and transformers – the extensive range of cold shrink and heat shrink joints and terminations are supported by a complete range of cable jointing tools to enable the removal of sheath, insulation and screen from LV, MV & HV cables.

Insulated Tools

Customised & Standard Insulated Tool Sets – Tested To IEC 60900: 2012.

Cable Jointing Tools - Boddingtons Electrical

Cable Jointing Tools for Low, Medium & High Voltage Jointers – Boddingtons Electrical

Further Reading