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Cable Strikes | HV Cable Joint Explosion

Cable Strikes

Utility Strike Avoidance Group

USAG have published a range of documents to assist industry understanding of the root cause and contributory factors behind specific incidents. The aim is to improve industry standards and reduce the number of cable strikes.

Cable damage is often caused by excavating machines – hand held tools such as pneumatic drills, crowbars, pins, picks and forks also expose workers to potential sources of danger when digging around underground cables.

Cable Hangers | Cable Ducting | Cable Protection | Electrical Safety Equipment

Incident Overview

What Happened?

A trial hole was excavated at a site in Wisbech, it was left open whilst other works on the site continued. Late in the evening an old clay cable joint surrounding an exposed steel wire armoured high voltage cable (11kV) exploded. The explosion set fire to roadside barriers that were lying over the hand excavated trial hole.

On the days prior to the joint failing it had rained but the excavation had not filled with water. The condition of the exposed cable and joint was believed to be in good condition when initially exposed.

The Fire Service and Police arrived on site, extinguished the fire and made the area safe. The loss of power affected approximately 1600 properties; thankfully no-one was injured.

What Do You Need To Do?

• Whenever you uncover a low or high voltage clay joint, or any type of cable joint which appears to be damaged or in poor condition, contact the local utility owner to inspect the joint before work continues in the immediate vicinity.
• Always support cables and joints in excavations appropriately, they must be suitable supported to prevent sag and strain on the joint.
• Never use other utilities to access and egress to and from excavations.
• Where possible use pumps to avoid excavations filling with water and submerging joints.
• Use appropriate security measures to keep members of the public safe.

Protecting Cables Against Strikes & Restoring Power Post-Strike

Thorne & Derrick have been distributors for 3M Electrical since 1985 and can provide a range of reliable and easy to install Cable Repair Products – this includes Scotch Tapes, Scotchcast Joints and Cold Shrink Tubes to provide effective re-instatement of cable sheath jackets on all types of LV MV HV cables in onshore and offshore locations with safe or hazardous area workplace classifications.

Cable Repair Products

Our range of cable protection covers manufactured by Centriforce provide underground utility protection of LV MV HV cables including Tapetile (11kV) and Stokbord (33kV 66kV 132kV) – contact us to discuss Cable Damage Prevention Products including Dectamesh, the underground detectable warning tape for alerting excavators of the presence of buried cables and to prevent potentially lethal accidents during excavation.

Stokbord

Tapetile

G&W Electric 220kV Cable Joints Installed To SGCC For 2016 G20 Summit

Geoffrey Cao (VP Global Operations – Energy Business) has kindly contributed the following Guest Blog emphasising the requirement for reliable high voltage electricity distribution and supporting cable accessories.

The Article explains the successful installation of G&W Electric cable joints and terminations to the State Grid Corporation of China, the largest electric utility company in the world and a state-owned transmission and distribution company.

In November 2015, G&W Shanghai received the mega 220kV cable joint order from the State Grid (SGCC) local company of Hangzhou City – the order comprised 88 units of cable joints and 6 units outdoor cable terminations for the 220kV extra high voltage network.

The project is to bury 2 circuits of 220kV overhead line to underground, as part of the infrastructure budget to renovate Hangzhou City to prepare for the G20 Summit that is scheduled in September 2016.

The G&W Electric products supplied are oil insulated outdoor terminations with composite insulator and pre-expanded cold shrink one-piece insulated cable joint.

G&W Electric 220kV Cable Joints Installed To SGCC For 2016 G20 Summit

Pictured: 220kV G&W Electric Cold Shrink One-Piece Cable Joints 

Pictured: West Lake in Hangzhou

After some international events like the 2008 Olympic Games, it is well known to the world, how structured the Chinese government arranges such events, thus the significance of this project is not only customer’s acknowledgement of the high quality and reliability of product being supplied, but also the ability of on time completion of project thus subsequent construction will immediately follow the cable project completion.

The delivery of such a large volume of cable joints for 2500sqmm cable, the largest 220kV cable size, were done within 1.5 months, thanks to G&W advanced moulding technology with such a high output, efficiency and yield rate.

As standalone EHV accessory company, G&W earned high reputation to work with many cable companies for the EHV cable system in past, and this time, the accessories will be coupled with several different Chinese local cable companies.

G&W is also providing the on-site installation of all accessories supplied, which is also featured with tight time schedule due to the forthcoming Chinese new year, thus constructors will have a long holiday.

“This mega project is another good example for G&W to demonstrate ability to supply bulk quantity of extra high voltage product and our versatility to work with different cable companies for important cable system work” commented by Mr. Jim Solari – G&W Electric.

Jointers blog

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Includes access to our popular JOINTERS BLOG with contributions from utility professionals, linesmen and cable jointers working on MV HV EHV cables and overhead lines typically at 11kV, 33kV, 66kV and up to 132kV.

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Cooper Connectors | Terminating MV Power Cable Onto GBE Transformer

Image: Danny Williamson – LV/HV Cable Jointer.

Pictured: 11kV Cooper Connectors Terminating MV Power Cables Onto GBE Transformer.

Cooper Power Series

Cooper Power Series are a part of the Eaton product range. Founded in 1947 under the name of Rural Transformer and Equipment Company, RTE developed many advances that significantly changed industry practices in underground distribution. It became part of Cooper Power Systems in 1988.

When RTE received a patent on the 15 kV loadbreak elbow design in 1966, its potential growth was probably unrealized at the time. It is estimated that there are well over 10,000,000 such elbows in service today. As a leading innovator in the industry, RTE continued to introduce new products for underground distribution systems. RTE was the first to develop non-gassing current limiting fuses. In 1994, Cooper Power Systems acquired Combined Technologies Inc. to expand their product offerings in current-limiting fuses.

Kearney engineers developed connectors, hardware and tools that made overhead line construction and maintenance easier, safer and more dependable. Family held and formed by James R. Kearney in 1926, it became a part of Cooper Power Systems in 1997.

Since then, Cooper Power Systems also came to incorporate Electromanufacturas, S.A. de C.V. (EMSA) in 1999, Cannon Technologies in 2006 and Cybectec in 2007.

Further Reading 

• Cooper Power | Bushing Interfaces & Separable Connectors Guide
• ANSI Connectors | Screened Separable Connectors from Cooper Power Systems
• Cooper Connectors Terminating 33kV Cable Onto Interface E Bushings

Jointing Masterclass – Waveform Mains & Hybrid Service Cable Joint

Image courtesy of: Antonia Stevenson

Pictured: Jointing Masterclass Using 185mm² Waveform for Mains and a Hybrid Cable for the Service Cable. Antonia attending her very first cable jointing masterclass in a jointing bay at Power Engineering Training Facility in Corby, Northamptonshire. Training provided by Richard Seaton.

Meanwhile, in a typical joint hole somewhere in the UK.

Yellow wellies on! Jointers tent up! Lunch in a puddle!

Perfect conditions for hippo’s and cable jointers…

Insulating Boots & Safety Shoes (LV MV HV 1000v 11kV 20kV)

Further Reading

• Masterclass : 110kV Cable Preparation & Termination Using Prysmian Outdoor Sealing Ends
• Cable Training School | 400kV Cable Jointing & Cad Welding 2500sqmm Copper Cables
• LV Jointer Training – LV1 Course Introduction to LV Cable Jointing (Wavecon) – Single & 3 Phase Services
• Electrical Safety – Arc Flash Accidents & Electrocution In LV-HV Installations

Jointers blog

Subscribe now to our POWER NEWSLETTER– a monthly email circulation packed with news, projects, videos, technical tips, training information, promotions, webinars, career opportunities and white papers.

Includes access to our popular JOINTERS BLOG with contributions from utility professionals, linesmen and cable jointers working on MV HV EHV cables and overhead lines typically at 11kV, 33kV, 66kV and up to 132kV.

15,000+ Subscribers. ➡

Brand-Rex Fibre Installation, Termination & Testing by Networx3

Image courtesy of: Caroline Earnshaw-Florczyk Commercial Director at Networx3 Limited. Networx3 are the leading installer of blown fibre in the UK.

Pictured: Fibre Cable Installation, Termination & Testing by Networx3.

Fibre manufactured by Brand Rex, Joint Boxes by Mainframe at London Underground Barking.

Main Contractor Balfour Beatty.

Brand-Rex is a leading developer of cabling solutions for network infrastructure and industrial applications. Mainframe Communications are your one-stop solution for fibre-optics, fibre-optic products and associated services – including TÜV and LUL approved products :

• Equipment frames, racks, cubicles, cabinets and housings
• Splice trays, pivots, cassettes, frames and tap boxes
• Cable management trays, assemblies and storage
• Pig-tails, patch cords, loose-tube and multi-way cables

Video: Networx3 was commissioned to repair an Emtelle 14/10 blown fibre duct for Cybermoor. Networx3 have blown over 500 metres of fibre optic cable for Cybermoor; a community owned co-operative providing a Wi-Fi broadband network for Alston Moor and surrounding areas.

Jointers blog

Subscribe now to our POWER NEWSLETTER– a monthly email circulation packed with news, projects, videos, technical tips, training information, promotions, webinars, career opportunities and white papers.

Includes access to our popular JOINTERS BLOG with contributions from utility professionals, linesmen and cable jointers working on MV HV EHV cables and overhead lines typically at 11kV, 33kV, 66kV and up to 132kV.

15,000+ Subscribers. ➡