Cable Joints & Terminations HV
Dangers Of Substandard Heat Shrink Cable Terminations On High Voltage Systems
January 2nd, 2018-
Uploaded By: Chris Dodds – T&D Distributors of LV, MV & HV Cable Terminations & Cable Joints
The following LinkedIn Comments provide some expert guidance, insight and advice on how to avoid the dangers of substandard installation of heat shrink cable terminations on high voltage systems. Generally, when categorising voltages we include 11kV and 33kV power systems into the high voltage (HV) definition.
However contractors, manufacturers and the industry would also argue that 11/33kV should be classified as medium voltage (MV) and HV commences at 66kV.
The Comments below were in response to the following site installation photograph of an 11kV cable termination. Let us know your thoughts and we will include to the thread in order to improve readers knowledge and reduce industry risk.

Scott Wilkie HV Power Distribution Engineer at Scottish Power – cable entry points through the cable gland plate would be better if centralised. Crossing cores with increased stress over insulation, clearly used to phase out the cable sections in the box. Would prefer to see 11kV single cores with a trifurcating joint outside of the cable box if that was possible.
♦ See: Cable Glands MV HV
Brendan Preece, P.E. HV Electrical Engineer – in addition to previous comment, use a high voltage two-hole compression lug that matches the two-hole terminal pad for good low-resistance metal-to-metal surface area contact.
♦ See: Cable Lugs & Connectors 11kV 33kV
Tony Haggis Director at Tony Haggis Consulting Ltd – the HV cable box is designed for single core cable terminations only. It’s impossible to use 3 core cable and maintain clearances between the cores – hence the black discharge marks. Not sure why anyone would use 3 core XLPE cable these days – single core triplex is cheaper and much easier to joint and terminate. Most UK DNOs and European utilities use it. There is no way to recover the heat shrink cable terminations other than cut all the cables out and replace with single cores with trifurcating joints outside. Also I’m amused by the use of the outdoor rainsheds – not only unnecessary but they also make the clearances worse.
♦ See: Cable Boxes HV High Voltage & Terminating 11kV Triplex Cables
Colin Woodman Team Leader & HV Cable Jointer DELPRO – I could be wrong but looking at it I am struggling to see where, other than down near the bottom of the heat shrink cable terminations, that the semi con screen had been cut and the mastic installed…cables must only cross where the semi con is still in tact. This is why HV cable terminations like this should be designed from the top down not from the cable strip up.
♦ See: Cable Jointing Tools
Tony Haggis Director at Tony Haggis Consulting Ltd – in view of Colin Woodman’s comment I’ve looked a bit closer at the picture and it could be salvaged by remaking the heat shrink termination using what we used to call a “crossed core” kit that we used to use with 11kV belted paper cable. This kit included heat shrink semicon heat shrink tubes that we used to screen the cores up to the stress control tube which was placed up near the cable lug.
Perhaps stripping off the existing cable termination and extending the core screen with semicon tubes could then place the stress control tubes up between the perspex phase barriers. I personally wouldn’t guarantee it as we don’t know what discharge damage has already been caused. If one was determined to use 3 core 11kV cable in this box then a top down screen off measurement would work but I would want the termination manufacturer’s view first. Looks like the semicon has been terminated taking a measurement from the crutch leaving unscreened core in the areas to be crossed.
I’ve always advocated taking the screen-off measurement from the HV cable lug thus leaving maximum screened core in the box. However, most termination manufacturers give a bottom up dimension but will give a top down dimension when asked.
♦ See: MV HV Cables 11kV 33kV
Michael White CEO at Campbell White – Colin you are spot on where a cross or a roll on end termination you must know creepage distance on these lineal stress terminations: on all Raychem terminations 90mm from top of black semiconductor heat shrink to open conductor then you can roll and cross on the semicon screen and have no trouble. There is no science taught these days on stresses and zero potential for cable jointers. I can understand third world jointers making mistakes but not educated ones.
♦ See: Cable Jointer Training Courses
Dan James MIET Technical Services Engineer – Senior Authorised Person at NG Bailey – complete mess. As suggested above this can’t be saved. Cut it all back, do a cable joint to single cores, get rid of them heat shrink sheds and perspex.
Richard Poulter SPS Managing Director – looks like a 33kV termination because of the phase barriers but more so the sheds per phase and the length of the stress control tubes which you can see the outline of below the anti-track tubes (they look about 260mm long). You can make out the semi-conductive screen ends because of the small bulge where the yellow stress tape is applied but most of the stress control tubes are fitted below this point rather than above it. So the majority of the stress tube is not doing anything.
I suspect the heat shrink cable terminations are fitted this low because the cable jointer was probably trying to achieve a distance of 250mm from the top of the stress tubes to the bottom of the lug barrels. The cable end termination box just does not look big enough for this voltage class termination, probably better to have used single core cable and they might have had a chance of achieving the cable spacings. Lots of discharge going on. That phase on the right looks like totally different anti-track but the intense heat has discoloured the other phases by the looks of things. Has it blown yet?
Maybe do a Trif joint below the cable box and take single cores in. If little space, use Raychem IXSU heat shrink kits or a cold shrink termination. Life expectancy is hard to pinpoint but there is a lot of discharge going on so they should schedule this within a week otherwise the damage will be a lot more. The temperature at the discharge can be as high as 1000 degC and once the carbon deposit increases on the cores, the quicker it will fail.
Andy O’Malley Allteck IBEW 258 EHV Cable Jointer/Splicer – they could have broke this 3 core cable into single cores outside of the 11kV box utilising jacket reintroduction kits and glanded the single cores individually and this would of been a perfect installation.
John Thompson High Voltage Cable Splicer – Okay, honestly it looks like hell. But let’s pick this apart. There are 12 cables in this picture (4 per phase). The 11kV terminations appear to be in some kind of a protected cabinet so they could operate for a length of time if this was some form of a temporary hookup. In my opinion this is more of an engineering catastrophe than a cable splicers mishap.
Joe Kinnane HV Electrician/ Transmission Cable Jointer With Western Power – they clearly needed to be “broke out” way lower than they have been with longer spaces between the stress point on the different phases! Heat shrink tubes weren’t pushed down fully on the breakout either.
HV Cable Terminations – A Report Into 11kV Heat Shrink Termination Failure
January 2nd, 2018
Contributed By: Watkins and Jacomb Construction Power & Consultancy
Uploaded By: Chris Dodds – Thorne & Derrick: Distributors of LV, MV & HV Cable Jointing, Cable Terminations, Substation & Electrical Eqpt
Cable Terminations
WJCPC are specialist LV HV Cable Termination & Jointing contractors with over 20 years experience in the High Voltage Electrical Industry covering the utilities, renewable energy, rail, data centre and general industry sectors – UKPN competent for LV & HV Termination and Jointing Of Cables, Confined Spaces, Substation Entry and Cable Fault Finding.
In the following post Ben Jacomb highlights 5 serious shortcomings across cable terminations installations on the same site – this installation investigation underlines the scope for jointer error at various key stages including critical cable preparation mistakes prior to installing the HV cable terminations.
Clearly under-trained, unskilled labour has been used to perform work normally carried out by highly-skilled, experienced and certified cable jointers.
This article covers the termination of BS6622 11kV 3 Core XLPE high voltage power cables – in a previous contribution WJCPC discussed and displayed the process of terminating 11kV Triplex cables.
- Steel Wire Armour – poor termination of the 11kV wire amours (SWA)
- Semicon Screen – failure to observe correct measurement and use correct jointing tools
- XLPE Insulation – undue care and attention by jointer when working on 11kV insulation
- Disregard Of Cable Termination Instruction – failed to apply the void filler correctly
- Cable Stripping – insufficient cable insulation on 11kV cable due to overstripping
“On behalf of one of our clients we were asked to complete several heat shrink terminations onto high voltage 11kV 3 core XLPE SWA power cables. After the first inspection of the HV cable terminations I was not satisfied with the cable jointers technique undertaken to remove the semi conductive layer, which had been done by using a semicon cable stripping tool. The high voltage semi conductive layer is semi bonded type so the stripping of the layer should be stripped by using a depth knife and the ringing of the stress control point on the 11kV cable by a soft file.

Thorne & Derrick are the UK’s largest stockist of cable jointing tools manufactured by Alroc.
Any marks left in the XLPE insulation of the 11kV cable will influence the magnetic fields inside the power cable and should be removed by emery cloth to leave a smooth finish eliminating any voids. If the heat shrink tube is shrunk on top of a void there will be moisture and where there is moisture there will be arcing, burning and then potential failure of the 11kV cable. If the semi conductive layer is not removed correctly at the crucial point then discharges arise causing damage to the cable.
♦ Further Reading: The Semicon Screen – A Most Critical Point In Any MV Cable Joint, Termination Or Connector.

Perfect Semicon Screen Cutback
Below are pictures and comments on several findings from recent 11kV cable termination inspections.
Steel Wire Armour
When terminating 11kV cables with heat shrink cable terminations there is a requirement to ensure safe earthing and termination of the armour wires (SWA steel wire armour) using cable glands, commonly referred to as “top-hat” cable glands.
In most 11kV cable installations the cable gland body can be installed after completion of the 11kV terminations. Completion of the final 11kV connections should be done before bolting the cable gland into place on the 11kV cable box.
Note, the correct jointing procedure for termination of the wire armour is to open-up or splay the SWA armours and bend back over onto the cable gland body and using worm drive clamps to connect the armour and screen earth braids to the gland body.
Before applying heat with a gas torch to the heat shrink tube, which is used to shroud and provide environmental and corrosion protection to HV cable terminations, the jointer can abrade the cable sheath and then using cable cleaning tissues thoroughly degrease the 11kV cable.
Insulated 11kV cable glands are also available for industrial medium/high voltage power systems with steel wire (SWA) or aluminium wire (AWA) cables.

Incorrect Installation Of HV 11kV Cable Glands

Correct Installation Of HV 11kV Cable Glands
Semicon Screen
The semi conductive layer cut back should be 20mm and not over according to the HV cable terminations instruction – on this cable installation the dimensional error was consistent on all 5 cable termination breakdowns with semicon screen layers averaging between 25mm – 40mm.

Semi Conductive Layer Length
Here, the semi conductive layer has been left on the 11kV XLPE insulation which can cause surface tracking and eventual flash over. This occurred on 2 out 5 cable termination breakdowns.

Semi Conductive Layer Left On The Cable Insulation
XLPE Insulation

Damage To 11kV Cable Insulation
Disregard Of Cable Termination Instruction
Here, the yellow mastic void filler has not been applied correctly by the cable jointer. It clearly states in the heat shrink termination kit instructions that 5mm of yellow mastic is to be installed on the copper tape screen and to continue over the semicon layer and then finish 10mm onto the cable installation. The yellow mastic is used to fill voids – the mastic provides stress relief from electrical fields so it is essential this is installed correctly.

Yellow Mastic Void Filler Not Applied Correctly On The Cable Terminations
Score marks on insulation – this will more then certainly cause flash overs as previously mentioned in this report.

Score Marks On 11kV Cable Insulation
Cable Stripping

The image above shows the XLPE cable insulation cut for a cable lug on one cable termination – the required insulation measurement is 5mm.
On all the cables that have been stripped using a stripping tool the cable jointer has left less then the minimum requirement of insulation needed around the conductor of the 11kV cable. The cable manufacturer has confirmed that the finished XLPE insulation around a conductor should be 3.4mm and any part of the insulation under the minimum of 2.95mm is a failure.
After breaking down 5 cable terminations to find 5 different failures on each one this is very concerning. I would not energise any of the 11kV cable terminations until further investigation.”
HV Cable Terminations
Thorne & Derrick distribute the most extensive range of HV Cable Terminations & Joints to suit 11kV/33kV medium and high voltage power cables, including indoor cold shrink and heat shrink terminations, outdoor pole-mounted terminations or separable connectors for gas insulated equipment applications.

HV High Voltage Cable Joints | Cable Terminations | Cable Connectors | MV HV 11kV 33kV

Joint | Terminate | Connect Medium & High Voltage Cables MV HV
THORNE & DERRICK are national distributors of Cable Installation, Jointing, Substation & Electrical Safety Equipment MV HV – we service UK and global businesses involved in cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.
Contact us for 3M Electrical, ABB, Alroc, AN Wallis, CATU Electrical, Cembre, Centriforce, CMP, CSD, Elastimold, Ellis Patents, Emtelle, Euromold, Filoform , Furse, Lucy Electric & Zodion, Nexans, Pfisterer, Polypipe, Prysmian, Roxtec, Sicame, WT Henley.
Invitation
Thorne & Derrick invite you to join LinkedIn’s largest LV-HV Electrical Discussion Group : Low & High Voltage Power, Cabling, Jointing & Electricals.
Discussion subjects include cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV. Network, engage and promote your profile, company or products with over 10,000 influencers.

I’m Now A 4 Day Cable Jointer
November 22nd, 2017
intro by Chris Dodds - Thorne & Derrick International
I woke recently and toyed with the idea of career change. One Costa later I just went for it.
So I Google searched “cable jointer training“.
I booked that 4 day course, turned up, collected my certificate – I am now a Cable Jointer.
With paperwork to prove it.
Easy-peasy.
Next move, carpet bomb LinkedIn recruiters with my new CV, sit back and wait for work.
OK, this is a personal fiction but a common occurrence in the UK jobs market.
There is increasing concern in the electrical industry in general and the Cable Jointing trade specifically about a trend of “fast-track” training courses propelling underskilled manpower into a crowded labour market. Inflicting damage on day rates, earnings and livelihoods.
We’re talking day rate differences of £150 v £500/600.
This is rather bloody serious – the view from the cable trench is that the industry is lawless and time-served experienced craftsmen are the furious victims. Some are fastly loosing faith in their trade, some would say their craft, some even their art. Their pockets are hurting.
There is not a skills desert out there but there is an unwillingness, in part, to recognise the monetary value of their skill, experience and ability.
A curative response is needed to stem the tide – no end of soul-baring spleen venting social media posts will remedy this situation. We’ve lamented the demise of “The Jointer” before – we’ve kicked up stinks and many have smelt the pong if not righted the wrong.
Nevertheless, lets continue the crusade and champion the real-deal Jointer.
Because in 4 days time more cable jointers will be on the job-market for hire.
But can they wipe, glass, strip, chamfer or plumb cable?

Two Times More Power. Jointers! Empower your CV and skill-set by grasping the 66kV Jointer Training opportunity. Jointers must currently be 33kV Competent and experienced to be ready to undertake the step-up to 66kV from 33kV.
Many cable jointers hold a diversity of accreditations from leading brands such as Nexans Euromold, Brugg, ABB, Pfisterer, Prysmian and 3M – they possess the expertise to joint across an extensive range of medium and high voltage cables (polymeric, gas and oil filled) using cold shrink, heat shrink or push-on HV cable joints, terminations and connectors.
This skill-set is developed over years and contrasts sharply with the generic jointer familiarised with the “specific joint for specific cable” approach of some training centres.
Of course, training is core to career progression without which young, skilled and gifted trainees could never develop – the industry would stagnate to eventual extinction.
Well we’ve blown the trumpet, now we need you – the industry – to rally to the call and let us know your thoughts and opinions. We will feature them on this Post.

The following TweetDeck demonstrates the skills levels and competency of an international class EHV Cable Jointer – Andrew Brezovszky is conversant with the cable jointing techniques required for medium voltage, high voltage and extra high voltage oil filled, gas filled or polymeric cables. 20 years of cable jointing experience with Competency Certificates from leading cable accessory manufacturers including Prysmian, ABB and Pfisterer.
What you might call a real-deal Jointer.

132kV Ericsson Transition Joint – 3 Core Cable Joint XLPE To Oil Filled Cable. Image: Energi Cable Services
Thorne & Derrick International
Since 1985 Thorne & Derrick based in the UK have been specialist distributors of LV, MV & HV Cable Installation, Jointing, Substation, Arc Flash Clothing & Electrical Safety Equipment including voltage detectors, insulating gloves and life saving substation intervention kits.
T&D customers include UK and worldwide contractors, specifiers, traders and end-users involved in cable installations, sealing cable ducts, cable jointing, substation, overhead line and electrical construction at Low, Medium & High Voltages.
We are specialist stockists and distributors of 11kV-33kV Cable Joints, Terminations & Connectors from manufacturers including 3M, Pfisterer, Prysmian and Nexans Euromold in a selection of jointing technologies including heat shrink, cold shrink and push-on.

Cable Innovation Tools & Accessories for Low & High Voltage Power Systems | HV Tools Information
Energy Skills Solutions – Training, Assessment & Consultancy Solutions
November 17th, 2017
a Guest Blog by Jonathan Andrews (Managing Director - Energy Skills Solutions)
Energy Skills Solutions is a registered training organisation based in Perth Western Australia offering training, assessment and consultancy solutions for the electrical supply and electrical industries.
Founded on the expertise and background of its Directors with a combined over 60 years’ experience in electricity supply industry operations and training, Energy Skills Solutions is committed to delivering the highest quality training, assessment and consultancy services.
Energy Skills Solutions prides itself on establishing and maintaining strong, mutually beneficial relationships with their industry clients.
We strive to be the training provider of choice for our targeted industries.
As a Registered Training Organisation, Energy Skills Solutions is obligated to deliver high quality, well managed and competitive services.
All Energy Skills Solutions operations are underpinned by its core values:
- Safety and environment
- Quality
- Professionalism
- Trust
- Responsiveness
- Flexibility
Services
Energy Skills Solutions offers a range of training, assessment and consulting services from Nationally Recognised Qualifications, Units of Competence and Accredited Courses to customised training to suit the individual client needs.
Services include:
Overhead Distribution Training
- Certificate III in ESI – Power Systems Distribution Overhead
- Energised power line insulator cleaning and coating
- High voltage live work glove and barrier
- High voltage live work distribution stick
Services & Metering Training
- Installation of customer services (overhead and underground)
- Installation of energy meters
- Service connection testing
Underground Cable Training
- Certificate III in ESI – Power Systems Distribution Cable Jointing
- Cable laying and pulling
- Installation of de-energised polymeric cables (high and low voltage)
- Installation of high voltage cable joints, terminations and connectors
- Energised low voltage polymeric cable jointing
- High voltage paper lead cable to polymeric cable transition jointing
- Cable fault location
- VLF cable testing
Switching Operations Training
- Overhead and underground field switching operations (high and low voltage)
- Electricity substation switching operations
- Commissioning testing (electrical equipment)
Vegetation Management
- Certificate II in ESI – Powerline Vegetation Control – Safety Observer & Vegetation Control Near Energised Low voltage
- Vegetation control near high voltage power lines
ESI Refresher and Electrical Safety Training
- UETTDREL14A Working Safely Near Power Lines (Non-electrical Workers)
- UETTDRRF01B Apply ESI Safety Rules, Codes of Practice and Procedures for Work on or Near Electrical Apparatus
- UETTDRRF02B Perform Pole Top Rescue
- UETTDRRF03B Perform EWP Rescue
- UETTDRRF04B Perform Tower Rescue
- UETTDRRF05B Perform Switchyard Structures At Heights Rescue
- UETTDRRF06B Perform Live LV Panel Rescue
- UETTDRRF07B Perform Cable Pit / Trench / Excavation Rescue
- UETTDRRF08B Perform EWP Controlled Descent Escape
- UETTDRRF09B Apply Access Procedures To Work On Or Near Electrical Network Infrastructure
- UETTDRRF10B Perform First Aid In An ESI Environment
- UETTDRRF11A Testing Of Connections To Low Voltage Electricity Networks
- HLTAID001 Provide CPR – Endorsed By St John
- HLTAID002 Provide Basic Emergency Life Support – Endorsed By St John
- HLTAID003 Provide First Aid – Endorsed By St John Assessment
Assessment services include:
- Service connection testing
- High voltage live work glove and barrier (annual)
- High voltage live work distribution stick
- High voltage live work transmission stick
- Recognition of prior learning
- Verification of competency
Consulting
Our consulting services include:
- Courseware design and development
- Procedure development and audits
- Training needs analysis and training plan development
- Systems development (training and assessment)
- Recruitment and selection support
Energy Skills Solutions delivers courses to optimise learning and make training both informative and enjoyable.
Electrical Safety
With safety seen as a reflection of an organisation’s commitment to its people, Energy Skills Solutions ensures safety is embedded into and an integral part of the services delivered.
In particular, Energy Skills Solutions uses training as an opportunity to influence and promote:
- a culture intolerant of unsafe practices and conditions
- an attitude of “there’s always time to do it safely” and
- “do it safely or not at all”
People
Along with the background and experience of its Directors, Energy Skills Solutions engages only the most skilled and knowledgeable trainers in the industry.
ESS unique arrangement means that trainers when not training can undertake field based work to maintain and build their technical skills and knowledge. Many of Energy Skills Solutions trainers operate their own electrical contracting or power line construction business.
Energy Skills Solutions trainers also hold the relevant Certificate IV training and assessment qualification.

Energy Skills Solutions – Training, Assessment & Consultancy Solutions
For further information please contact Energy Skills Solutions so they can assist you with your training requirements.
Administration: P: 0892093833 E: [email protected]
Website: https://energyskillssolutions.com.au/
Jonathan Andrews – Director- M: 0421717287
THORNE & DERRICK are national distributors of LV, MV & HV Cable Installation, Jointing, Duct Seals, Substation & Electrical Equipment – we service UK and global businesses involved in copper earthing, cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.
Specialists in the jointing and connection of 33kV power cables using Nexans Euromold separable connectors for terminating cables into medium/high voltage switchgear and transformers – large UK stocks of Pfisterer Plugs, Nexans Connectors and 3M Cold Shrink Joints & Terminations.

MV HV Cables 11kV 33kV – Joints, Terminations & Connections
Since 1985, T&D have established an international reputation based on SERVICE | INTEGRITY | TRUST.
Contact us for 3M Electrical, ABB, Alroc, AN Wallis, CATU Electrical, Cembre, Centriforce, CMP, CSD, Elastimold, Ellis Patents, Emtelle, Euromold, Filoform , Furse, Lucy Electric & Zodion, Nexans, Pfisterer, Polypipe, Prysmian, Roxtec, Sicame, WT Henley.
Invitation
Thorne & Derrick invite you to join LinkedIn’s largest LV-HV Electrical Discussion Group : Low & High Voltage Power, Cabling, Jointing & Electricals.
Discussion subjects include cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV. Network, engage and promote your profile, company or products with over 10,000 influencers.

Pragmatic Consulting – Bespoke & Technical Training Courses
November 17th, 2017

a Guest Blog by Jo Niblett (Managing Director - Pragmatic Consulting)
Pragmatic Consulting are a leading engineering consultancy business with a training and assessment centre working within the utilities industry approved to deliver BESC AME assessments along with other training courses such as manual handling, first aid and other related qualifications.
BESC AME assessment courses are for anyone who carries out work either directly or indirectly in the power utility industry – including cable jointers and wiremen working on low, medium or high voltage cables, overhead lines, substations or switchgear.
Pragmatic Consulting offer a range of courses that meets the needs of the electrical and power industry and are prepared to travel and provide training events across the UK so that you are able to have training when it suits you.
Pragmatic Consulting approach each course in an individual manner to ensure that the candidates who pass through the door are trained to the highest standard whilst ensuring that they receive whatever support they require to help them progress and achieve.
Cable Jointers
Compliance vs Competence
A common debate I have, Compliance vs Competence, what is the difference?
Is simply being compliant enough?
Does a ticket equal competence?
And how is competence measured?
Compliance is ‘acting in accordance with health & safety rules and legislation’.
Compliance is a minimum requirement, while competence goes above and beyond that.
The definition of competence from the HSE website: “To be competent an organisation or individual must have sufficient knowledge of the tasks to be undertaken and the risks involved. They must have the experience and ability to carry out their duties in relation to the project, to recognise their limitations and take appropriate action to prevent harm to those carrying out construction work, or those affected by the work.”
Competence develops over time.
It is a mix of initial and on-job training, instruction, assessment and formal qualifications.
The difference between compliance and competence can be thought of as: Passing and getting your driving license you are compliant; you know how to drive and all the rules and road theory. But are you a competent driver? You are now on your own and putting the knowledge you have learned into practice. But without experience you are only compliant.
For further information on the courses that Pragmatic Consulting offer please visit https://www.pragmatic-consulting.co.uk/ or contact Jo Niblett (Managing Director).
Tel: 01926 674340
Mob: 07747 740311
Email: [email protected]

THORNE & DERRICK are national distributors of LV, MV & HV Cable Installation, Jointing, Duct Sealing, Substation & Electrical Equipment – we service UK and global businesses involved in cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV.
Since 1985, T&D have established an international reputation based on SERVICE | INTEGRITY | TRUST.
Contact us for 3M Electrical, ABB, Alroc, AN Wallis, CATU Electrical, Cembre, Centriforce, CMP, CSD, Elastimold, Ellis Patents, Emtelle, Euromold, Filoform , Furse, Lucy Electric & Zodion, Nexans, Pfisterer, Polypipe, Prysmian, Roxtec, Sicame, WT Henley.
Invitation
Thorne & Derrick invite you to join LinkedIn’s largest LV-HV Electrical Discussion Group : Low & High Voltage Power, Cabling, Jointing & Electricals.
Discussion subjects include cable installations, cable jointing, substation, overhead line and electrical construction at LV, 11kV, 33kV and EHV. Network, engage and promote your profile, company or products with over 10,000 influencers.


Evan Paul Galleozzie Approved Electrician – bad design of the entry of the 11kV cables which has resulted in a mess of the cable terminations. And a few of the the cables look in a poor condition. And the CPC’s could have been installed properly using crimping tools, too much copper showing. Bad, bad, bad.
Christopher Williams Head of Services and Support at IPEC Ltd – looks like a severe case of surface tracking on the heat shrink cable terminations (a form of partial discharge). This is likely caused by the inadequate installation of the feeder cables increasing the electrical stress across the surface of the high voltage cable insulation. Any dirt/dust/contamination would then have helped create small electrical discharges across the insulation causing the carbonisation you see in the image. Over time this will compromise the insulation further, finally resulting in a catastrophic failure. Interestingly, this could have been detected via PD monitoring, in this case, ultrasonic emission would have been emitted and sensors could have detected the inception and location of this defect long before it got to this stage!!!
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Suppliers of HV Joints, Terminations & Connectors
Thorne & Derrick distribute the most extensive range of MV HV Medium & High Voltage Cable Joints, Terminations & Connectors from manufacturers including 3M, Prysmian, Nexans Euromold, Elastimold, Pfisterer CONNEX and Shrink Polymer Systems.
Heat shrink, cold shrink, push-on and slip-over cable accessories enable the jointing, terminating and connection of 11kV-33kV and 66kV-132kV cables to oil, air or gas insulated switchgear, transformers, motors and overhead lines distributing electricity at MV HV.
Thorne & Derrick stock 11kV 33kV 66kV Joints & Terminations suitable for XLPE, PILC and EPR cables, in both heat shrink and Cold Shrink technologies, to service the medium/high voltage power cable accessory requirements of UK and international customers.
Stockists & Distributors of High Voltage Joints Terminations Connectors