Cable Jointing - An Art or Science?

By Chris Dodds on 12th August, 2015

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Both.

Whether lashing in a Straight 6 resin splice to power a domestic shower or jointing 110kV cables to energise Brisbane, the cable jointer must concentrate during all stages of cable stripping, measurement and joint installation.

Make an error with your measure, flirt with failure.

Of course cable failures keep cable jointers busy.

But self-inflicted cable failures caused by bad jointing and the "jointer" will soon be hanging up his crimper.

Quick joke. What's the difference between a Jointer and a Doctor? A Doctor buries his mistakes - a jointer digs his up! Tumbleweed rolls through Blog.

Cable failures caused by poor jointing are costly.

Reputation damage plus consequential losses incurred by a powercut then multiplied by cost of the supply restoration as a formula is simply incalculable.

However, the ability to understand and apply complex mathematical formulae is a required staple of an EHV jointers skill-set.

Andrew Brezovsky is amongst many other things an EHV jointing legend and social media megastar. I suggest you Connect with Andrew on LinkedIn now - but don't forget to hit the back button and rejoin us for a lesson in advanced cable jointing.

Cable Jointing Science

In todays lesson, Andrew considers the importance of the theoretical formula and the practical skill required in calculating and installing premoulded sleeves when jointing 110kV cable. 

Removing the semi-conducting screen and installing the premoulded cable joint sleeve is a critical stage of jointing 110kV cables.

"So the calculation of the length of the premoulded sleeves when fitted is relying on the length of the mould, inner bore diameter of the tube, insulation diameter and the inner bore of the mould," says Andrew.

Therefore, referring to the featured image above the calculation for the length of the premoulded sleeves is as follows :

• LS = length of cable joint mould when landed
• Z = overall length of mould as supplied
• A = inner bore diameter
• C = diameter of PVC tube
• Y = diameter of sleeve on PVC tube
• B = cable insulation diameter

Cable Jointing Art

"Here are a few shots from the mould loading process. The mould is being forced onto that PVC tube with the machine and silicone oil used as cable lubricant. The landing position is calculated individually for every cable joint to the point of a millimetre. You have to be good with your maths as the formula as you now know is complicated," informs Andrew.

Images by EHV Cable Jointer : Andrew Brezovszky (EHV Cable Jointer - Energex Australia).

 

• Further reading

110kV Oil Filled Taihan High Voltage Cable Joints

110kV Prysmian Plug-In Cable Termination For SF6 Gas Insulated Switchgear

110kV Prysmian Screen Break Cable Joint - EHV Extra High Voltage

33kV Trifurcating Transition Cable Joint : 3 Single XLPE Cables to 3 Core HSL PILC Cable

 

Thorne & Derrick Specialist Electrical Distributor

Established since 1985, T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Pulling & Installation Equipment - contact us today for a competitive quotation.

Key Products : MV Joints & Terminations, Cable Cleats, Duct Seals, Cable Transits, Underground Cable Protection, Jointing Tools, Feeder Pillars, Cable Duct, Earthing & Lightning Protection, Electrical Safety, Cable Glands, Arc Flash Protection & Fusegear.

Distributors for : 3M, Pfisterer, Nexans Euromold, Elastimold, Catu, Roxtec, Emtelle, Centriforce, Lucy Zodion, Alroc, Hivotec, Cembre, Prysmian, Ellis Patents, ABB & Furse.

 

Invitation

Thorne & Derrick are inviting you to join LinkedIn’s fastest growing Discussion Group : Low & High Voltage Power, Cabling, Jointing, & Hazardous Area Electricals (LV-HV).

Discussion subjects include cable installations, cable jointing, electrical 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.

 

Category:  Cable Jointing - PhotoBlog

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