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HV Cable Current Ratings For A Challenging Installation

HV Cables in Multiple Backfills

HV Cable Current Ratings

FEM Current Rating Solution

The customer required HV cable current ratings for an installation involving multiple (6) zones of backfilled soil with Thermal Resistivity (TR) varying between 1.2 – 5.2 K.m/W plus the resistivity of the native soil needed to be considered.

The IEC Standard methods do not cover such a complex installation. The most IEC 60287 can deal with is a single backfill. The native soil thermal resistivity was 1.5 K.m/W which is lower than the backfill areas – the IEC Standard equations are invalid for this condition alone.

The Finite Element Method (FEM) was needed to accurately solving the heat flux distributions for this installation.

How does the FEM model work?

In FEM the space is subdivided into smaller parts known as finite elements using a technique called meshing. These elements take the shape of a tetrahedron or a triangle.

The domain of interest is space discretized and this discretization is implemented by constructing a mesh of the object. The formulation of finite element method results in a system of algebraic equations.

These equations that model the finite elements are then assembled into a larger system of equations that models the entire problem. The solution to the problem is reached by minimizing the mean squared error error function.

For the analysis of HV cables, it is assumed to be in a 2D space. The heat generated by the cable conductors is considered along with the ambient temperature. The FEM model creates the temperature array and a large set of equations are solved.

Another important consideration of the HV cable system which is modelled using FEM is the ground surface and ambient air temperature interface which involves heat convection – this aspect is neglected using the IEC method.

How much difference does FEM make?

The calculated current ratings of HV cables using FEM cannot even be compared with the (approximate) IEC Standard method because the standard method is not valid for this installation.

The current rating for the 11kV single core, 300sqmm copper conductor cables surrounded with 6 zones of soil with different resistivity as well as the native soil resistivity, soil ambient temperature of 25 deg.C. and soil/air interface was as follows:

FEM method = 283 A.
IEC method (uniform soil resistivity 5.2 K.m/W) = 201 A (-29 % underestimate).
IEC method (uniform soil resistivity 1.5 K.m/W) = 366 A (+29 % overestimate)

In conclusion, only using FEM will give an accurate calculation of HV cable current ratings for this complicated installation.

Jayson Patrick – Technical Director, Electrotechnik

Jayson is the Technical Director at Electrotechnik, a company which develops leading electrical power system design and analysis software and has extensive experience working on large-scale power systems projects in high voltage design, testing/commissioning, and power system analysis roles along with two decades of experience in professional software development.

Jayson has a master’s degree in electrical power engineering and is a professional software developer. He leads a multi-disciplinary team of developers, cloud architects, UI designers, electrical power engineers and PhD researchers. Jayson’s role at Electrotechnik involves developing new software and complex algorithms for electrical power systems design, where he is using a combination of technologies, multiple programming languages and Agile development practices.

Jayson has a passion for UI and UX design and believes in building powerful software which is accurate while being intuitive and easy to use.

Jayson will be delivering a talk at Earthing Conference UK in Birmingham this month.

1:30pm – Day One

Analysis of Earthing Grids in Multilayer Soils at High Frequencies

Jayson Patrick – Technical Director, Electrotechnik

Modelling earthing system behaviour during both power frequency fault conditions and at high frequencies, especially related to lightning phenomena, is of interest to earthing system designers. The behaviour of earthing systems at varying frequencies is quite different and this paper will present details of the algorithm developed and results in the form of a parametric analysis for multiple grids in different soil conditions for high frequencies.

THORNE & DERRICK

T&D are Specialist Distributors to UK Distribution Network Operators (DNO’s), NERS Registered Service Providers, ICP’s and HV Jointing Contractors of an extensive range of LV, MV & HV Jointing, Earthing, Substation & Electrical Eqpt – this includes 11kV/33kV/66kV cable joints, terminations and connectors for both DNO and private network applications.

Contact our UK Power Team for competitive quotations, fast delivery from stock and technical support or training on all LV-HV products.

Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV HV 

Register to the SAP Talent Pool for Career Opportunities in the UK & Global Wind Industry

• uploaded by Chris Dodds | Sales & Marketing Manager at Thorne & Derrick

Thorne & Derrick are privileged to partner with EDS HV Group and support career opportunities within the Wind Industry via their Talent Pool. 

Are you an existing Senior Authorised Person (SAP) within the wind industry?

Are you an existing HV High Voltage SAP working in a similar industry looking to make a career move into renewables ?

If so, check out the EDS HV SAP Talent Pool and register your details below today  – this is an opportunity to join one of the fastest growing businesses servicing a wide range of clients within the renewable power industry.

EDS HV Group is a leading authority in the design, installation, operation, maintenance, and repair of high voltage windfarms. Mainly operating in the UK and Europe, EDS has been serving renewables for over a decade and impacting every stage of the wind farm lifecycle.

Due to the growth of EDS they are looking for experienced staff with specific HV SAP experience, with suitable qualifications for a role within the wind industry.

EDS have opportunities across several geographical areas including UK sites, Europe, Taiwan and Japanese sites.

EDS is an innovative and fast-growing organisation with highly skilled teams that enable them to deliver solutions to the most demanding operational and technical challenges faced by their Customers.

EDS HV Group SAP team members will have the following:

• In depth technical knowledge of HV networks particularly the UK, Europe and APAC.  Or can demonstrate a high degree of technical competence within their field of experience
• High degree of technical knowledge and analytical skills required to deliver world class HV Network Asset Management performance
• 400/275/132kV SAP, with the requirement to become authorised under the EDS HV Safety rules. Familiarisation training will be provided for the on-call sites
• Wind and Renewables experience transferrable skills from similar industries with HV electrical networks
• Fluency in written and spoken English, ideally with a second language

Essential: An existing SAP (could be 400/275/132 or 66kV), with the requirement to become authorised under the EDS HV Safety rules and customer site safety rules

If you have experience in the above specialism then EDS want to hear from you!!

Complete your application and submit your CV to them now.

Please note this is a Talent Pool, therefore you will only be contacted by EDS when a role becomes available and if your CV is suitable.

If you do see a specific role advertised on the EDS careers site please do apply for that in addition to your CV being in this Talent Pool.

• EDS HV Group Services
• Termination & Testing
• High Voltage Operations & Maintenance
• Turnkey Fault Location & Repair
• High Voltage Commissioning
• Wind Farm Asset Management

• Explore EDS

Specialist Distributors of High Voltage Jointing & Electrical Safety Equipment

Thorne & Derrick International are Specialist Suppliers to the UK and international Offshore Wind Industry of products to provide safe and reliable LV HV Electrical Cable Termination, Jointing, Installation & Power Systems up to 66kV.

We are based in North-East England, recognised as a key strategic location to service the offshore renewables energy market in the UK, from the North Sea to the Nordics – our Exports Division support international offshore wind power projects from USA to China.

Key Product Categories: Connectors, Joints & Terminations MV HV | Cable Preparation & Jointing Tools | Duct Seals | Cable Transits | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Clothing & Protection | Cable Pulling | Earthing & Lightning Protection | Feeder Pillars

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 & SEANEX.

May 2022 VOLTS!

THORNE & DERRICK LV HV Jointing, Earthing, Substation & Electrical Eqpt

Welcome to our industry bulletin – VOLTS.

So what is VOLTS?

VOLTS is our monthly round-up of industry news, projects, videos, technical tips, training information, promotions, webinars and career opportunities from Thorne & Derrick. Take a moment to Follow Us on LinkedIn to receive future VOLTS.

pROJECTS & NEWS

We Can Help

Thorne & Derrick are the Nexans Power Accessories stockist and UK Approved Distributor.

We offer the following 33kV ranges from stock at competitive prices – try us, we can help.

* JTS 33kV Joints – ex stock
* MONO 33kV Terminations – ex stock
* EUROMOLD 33kV Separable Connectors | T Boots – ex stock

To satisfy increasing market demand and our expanding customer base we are bolstering and extending all Nexans stocks. Should you require excellent customer service, supported by stock and underpinned by competitive prices, we can help.

Whether you are required to Connect 33kV cables using Separable Connectors into gas insulated equipment with inner cone (Size 3) or outer cone (Interface C) bushings or use conventional heat shrink technology to Terminate onto AIS, we can help.

If you require 33kV Joints or Jointer Competency Training, we can help.

Pictured | Picked & Packed & Shipping Out Today | Customer order despatched today to a UK wind farm project from our Bristol distribution centre which holds in excess of £1m stock of LV HV Jointing, Tooling, Earthing, Substation & Electrical Eqpt up to 66kV.

Read Press Release | Record Business Growth for T&D and Nexans Power Accessories

Sealing 132kV Cables

Thorne & Derrick distribute extensive cable sealing solutions for the effective flood defence and fire protection of medium and high voltage substations and LV power distribution ducting systems – we work closely with the UK DNO’s and their contractors to supply Approved Equipment from leading manufacturers. Here is a recent Case Application:

• Client: SSE (UK DNO)
• Product Category: Duct Seals
• Application: Sealing Extra High Voltage Cables & Ducts Against Water, Gas & Fire
• Voltage: High Voltage 132kV
• Sector: Renewable Energy (Wind)
• Product Installed: Filoseal+, Filoseal+HD and Filoseal+ HD Fire Cable Duct Sealing System
• Project Information: All 3 types of Filoseal cable duct seal systems were required; original Filoseal+ with foam backing, newer Filoseal+HD for heavier POWER cables and the newest seal type Filoseal+HD FIRE which adds BS EN1366 Part 3 with up to 4 hours of fire protection. All cable duct seals were installed according to instructions whilst special guidance and tips were given on site by the manufacturer.

Sealing Cables, Switch Hall & Grid Transformer Bases On 132kV Wind Farm

3M Electrical Stock Investment from Socket to Substation

T&D have distributed 3M Electrical Products & Cable Accessories since 1985 and this month we have committed to an additional £100K stock holding boost to support additional customer demand, project awards and mitigate supply chain bottle-necks in the marketplace.

From the humble roll of Scotch Tape to the lofty QTEN 66kV Termination, we can help.

LV MV HV Cable Abandonment Joints Terminations from 600v to 66kV Ex Stock.

Thorne & Derrick stock the most extensive range of LV Cable Joints from the Scotchcast Resin range of 3M Electrical for industrial and hazardous area cables including power, control and instrumentation.

Pictured: The QTEN 96-EP range of Cold Shrink Terminations stocked by Thorne & Derrick are suitable for the test, termination and connection of 66kV/72.5kV power networks

QTEN 66kV Features of the Termination

• The versatile design of the silicone Cold Shrink Termination body allows installation on a wide range of cable sizes and types and a fast and easy installation at temperatures ranging from -20°C to + 50°C
• No heat, flame, or special tools are needed during cable splice body installation
• Accommodates crimp or mechanical cable lugs up to 110mm in diameter
• Wide application range covering several cable cross sectional areas from 120sqmm –1500sqmm
• Solderless earth connection to copper screen wires or lead sheath
• Silicone rubber Cold Shrink outer rain sheds and sealing PST’s provide physical protection and moisture sealing of the completed cable termination
• Silicone outer rain sheds of the termination makes it ideal for zones with maximum environmental contamination, industrial or coastal
• Creepage path connection for additional protection in areas of high pollution

And The Winner Is……

Congratulations to Declan O Hara, your prize is in the post. Thanks PFISTERER for donating the copy of the Centenary Book.

PFISTERER meets future challenges with the knowledge that comes from one hundred years of experience. This expertise has developed continuously with advances in technology. Numerous innovations and patents continuously drive our growth with further investment in R&D planned for 2022 and beyond. Read more about our established relationship: Thorne & Derrick | Product Training With PFISTERER

Congratulations Harry

Just 10-years after joining Ellis Patents straight out of school as their very first trainee design engineer, Ellis the world-leading UK based manufacturer of cable cleats have promoted Chartered Engineer, Harry Taylor to the role of Technical Manager.

Talking about Harry’s promotion, Managing Director of Ellis Patents, Danny Macfarlane said: “We put a lot of focus on developing careers for young, local people and to see what Harry has already achieved is a source of great pride for us all.”

“He’s been a key member of the product development team since graduating with his first degree; and has been behind a variety of recent cable clamps innovations that have all had a big market impact – including an update to our 2 Hole Cable Clamp range that has seen the new product series sell three quarter of a million units since its re-launch.”

Tools | HV & FO

Pictured | A consolidated customer order, comprising over 100 Tools & Consumables prepared for despatch from Thorne & Derrick to a leading High Voltage Power & Jointing Contractor in the renewable energy sector – we can assist with an extensive range of Cable Accessories & Tooling to enable the installation, termination and test of both FO and HV cables up to 66kV. Find more info here about HV & FO Tools for Wind Farm Projects.

FO Tooling | Fibre Optic Strippers, Kevlar Cutting Tools, FO Cable Sheath Jacket Strippers, Spirit Level, Tweezers, Bent Nose Forceps, Angled Long Nose Pliers, Flare Nut Spanner, Jointers Knives, Flat Terminal Screwdrivers, Junior Hacksaw, Power Cutters, Worklights. Brands including Miller, Bahco & Knipex.

HV Tooling | Sheath Strippers, Semicon Screen Strippers, Insulation Removal Tools, Ratchet Spanners, Soldering Iron, Heat Shrink Gas Torch, Diameter Tape, Vernier Calipers, Nylon Hammer, Jointers Knife, Wire Brush. Brands including Alroc, Boddingtons & Sievert.

Tools for the Stripping & Preparation of FO & HV Cables

Staff Training

Thorne & Derrick are delighted to work with a supportive supply chain who provide training for our staff to aid their continued professional development.

Special thanks to Matt Page from Lucy Zodion for visiting our offices this month to provide training to our Sales Engineer Sarah Henderson on their EV & Pre-wired range of Feeder Pillars. Sarah has recently moved into her sales role and is progressing rapidly – she has become our Feeder Pillar specialist and is taking orders daily.

Sarah with Matt from Lucy Zodion

Industry event

Earthing Conference

Thorne & Derrick are Official Media Sponsors & Exhibitors at IDC Technologies, Inc. Earthing Conference UK which took place at the Park Regis Birmingham this month.

The aim of this conference was to demystify the subject of earthing and present the subject in a clear, straightforward manner. Earthing as a subject has been under-represented over the years and this event will attempt to remedy the gaps in technical knowledge and improve practices in the industry. The UK & Europe need a unified practical approach to earthing which can be commonly understood and widely applied.

Jonathan Hewitt (sales engineer) said: “It was great to be back to the face to face at the conference. Lots of people attended and there were some fantastic speakers.”

Special thanks to our partner AN Wallis for attending alongside Thorne & Derrick.

Sales Engineer Jonathan Hewitt with Jason Leatherland from A. N. Wallis

Top of The Posts

STRUTSLAYR

Clean, Consistent, Cuts – A Cutting Edge Innovation!

Alex Hart from Klauke visited our offices to provide an in-person demo to the team of the RIDGID® STRUTSLAYR™ Strut Channel Cutter. A short clip of the demonstration was shared on LinkedIn, which received fantastic engagement and several shares.

The StrutSlayr has been flying off the shelves since the start of the year and is said to be a ‘game changer’ for cutting strut in the industry. Time saving, burr-free and efficient ➡ Read more about the StrutSlayer.

Technical Tips

Cut & Crimp Cables with Total Safety 

Insulated Cable Crimping & Cable Cutting Tools | ORANGE by Klauke

Klauke have launched the Klauke Orange range of fully insulated cable crimping & cable cutting tools that have set the standard within the global utility industry – working with underground cables and overhead lines presents a series of challenges: proximity to potentially live parts, limited space and time pressures.

The world‘s first battery hydraulic crimping and cutting tools with Tri-Insulation Barrier technology that provides users with 1000V protection against electrical shocks.

E-LEARNING

Here is a list of FREE Monthly Webinars created by Ian Griffiths from greymatters providing technically secure answers to your HV Earthing or Lightning Protection Design questions. The library of Webinars can be accessed from the link below. You can earn CPD units and receive a certificate for participating.

• Why Is The DNO Refusing To Energise – ‘Hot-Site’ Problems?
• Why Am I Getting A Hot Site?
• The Top 3 Most Useful Webinar Takeaways From 2021
• Are You Struggling To FoP Test An Earth In A City Environment? Try This
• Stop Struggling With Rolling Sphere Designs! Watch This And You Decide – XGSLabs 10
• Surge Protection – How To Find Out If Your SPD Is Working
• Earth Testing For Dummies – Common Mistakes To Avoid
• Earthing Design Series Part 2 – What Is A Touch/Step Voltage Hazard?
• Bringing Your Earthing Design To Life
• Earthing Design Series – Part 1
• Lightning Protection Myths Busted And Solutions For The DSEAR/COMAH Sites
• An Introduction To EMF And Why We Need To Understand It.
• Model Lightning Strikes Using XGS
• Soil Resistivity Part 3 – How The Seasonal Changes Affect The Electrode Performance/Behaviour
• Soil Resistivity Part 2 – How To Process The Data
• Using Earthing Software – It Should Be Childs Play.
• Hot Sites Or Transferred Potentials
• Split Or Reduction Factors
• Earthing In Difficult Geologies
• Soil Resistivity Part 1 – Testing, Avoid The Common Mistakes
• ➡ Go to all FREE Monthly Webinars here

  

  

  Earthing & Lightning Protection

Featured Contractor

Exemplary workmanship and Competency is demonstrated here by Heighway Ltd, a UK leading Power & Cabling Contractor, who recently completed a Civils and Electrical Package to enable grid connection of a 5MW solar farm. As well as 33kV Jointing & Connection services, Heighway Ltd provided the following services:

• HV Cable Diversion Works
• HV Cable Installation to New Customer Substation
• HV Park Feeder & VT Connections
• HV Current Transformer
• Installation of COP3 Metering Panel 

All excavation works in and around DNO compound to include installation of new concrete bases was completed by Heighway Ltd.

Pictured: Nexans Euromold Type C Connectors Terminating 33kV Cables

Heighway Ltd | Supplying Electrical Services, Power Connection, Jointing & Termination Solutions to the Energy, Rail & Construction Sectors up to 33kV

33kV SAP’s | 33kV Jointers |  400v Live – Testing & Commissioning Engineers | Protection Engineers  | Design Engineers | HV/LV Fitting Teams | Civils/Digging Teams  | Skilled PTS Operatives (Rail) – Specialist Lifting Services

Jobs

Thorne & Derrick are privileged to partner with EDS HV Group and support career opportunities within the Wind Industry via their Talent Pool. 

Are you an existing Senior Authorised Person (SAP) within the wind industry?

Are you an existing HV High Voltage SAP working in a similar industry looking to make a career move into renewables ?

Thorne & Derrick distribute the most extensive range of Low & High Voltage Cable Installation & Electrical Distribution Equipment to the Power Transmission & Distribution industry in the onshore and offshore wind, solar, rail, oil/gas, data centre, battery storage and utility sectors – this includes Joints, Terminations & Connectors to enable the installation of low, medium and high voltage power cables into underground trench or duct.

Key Product Categories: Connectors, Joints & Terminations MV HV | Cable Preparation & Jointing Tools | Duct Seals | Cable Transits | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Clothing & Protection | Cable Pulling | Earthing & Lightning Protection | Feeder Pillars

Main UK Stockists for: 3M Electrical, PFISTERER Connex, Nexans Power Cable Accessories (Euromold), Alroc, Ellis Patents, ABB, Roxtec, Cembre & CATU Electrical.

Volts! Archive

• Volts! #1 January 2022
• Volts! #2 February 2022
• Volts! #3 March 2022
• Volts! #4 April 2022

WITHDRAWN IEC 61914:2015 | Cable Cleats For Electrical Installations

This article is intended to highlight IEC standard and specification updates in relation to short-circuit testing and purchasing of cable cleats.

The previous 2nd Edition of IEC 61914:2015 has now been withdrawn and replaced with IEC 61914:2021 – the 3rd Edition of the standard. This edition constitutes a technical revision of which we will detail below. 

All cable cleats distributed by Thorne & Derrick are currently undergoing testing procedures to conform to the latest IEC 61914:2021 standards.

Certification will be in place before the deadline.

So What’s Changed?

IEC 61914:2015 Is Withdrawn

The new standard is available as IEC 61914:2021 CMV which contains the International Standard and its commented version, providing a quick and easy way to compare all of the changes between IEC 61914:2021 edition 3.0 and the previous IEC 61914:2015 edition 2.0.

View the document here.

IEC 61914:2021 specifies requirements and tests for cable cleats and intermediate restraints used for securing cable in electrical installations. Cable cleats provide resistance to electromechanical forces where declared. This document includes cable cleats that rely on a mounting surface specified by the manufacturer for axial and/or lateral retention of cables.

This third edition cancels and replaces the second edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:

a) Requirements for mandrels used in testing rationalised and detailed in the general test requirements (Clause 5);

b) Definition of liner added and test requirements where liners and other optional parts are used;

c) Definitions for LV, MV and HV cables added and test requirements where MV & HV cable are used ;

d) New corrosion resistance classes for plated products added;

e) New requirements and test for durability and legibility of markings added;

f) New test requirements for axial load testing of cleats for more than one cable added;

g) Lateral load test requirements for intermediate restraints added

“Cable cleats are critical electrical safety products – in the event of a short circuit they can protect your people, not just plant. During a recent tender bid we were alerted to non-conformance of a competitor product during the technical qualification procedure for a major UK infrastructure project. Simply, their product was tested to the cancelled 2009, not superseding 2015 version. Thorne & Derrick distribute LV HV Cable Accessories & Electrical Equipment from market-leading manufacturers tested to the current range of international standards,” comments Chris Dodds (Sales Manager at Thorne & Derrick).

“The closest example I can think of for this is car seat belts. If you were on the market to purchase a car and were advised that the seatbelts on the car you had chosen were not compliant to the latest industry standards, you may decide against purchasing that car due to safety concerns. Moreover the car would not be safe for sale in UK or European markets and would not bear the required UK CA or CE mark. Cable cleats for cables can be viewed in a similar way to seatbelts in cars as they both perform safety functions, adds Noman Shabir (National Sales Manager at Ellis Patents).

All cable cleats stocked and supplied by Thorne & Derrick are short-circuit tested to the current updated version IEC61914:2015, and are undergoing testing to achieve IEC61914:2021.

Specialist Distributors of High Voltage Jointing & Electrical Safety Equipment

Thorne & Derrick International are Specialist Suppliers of products to provide safe and reliable LV HV Cable Termination, Jointing, Installation & Power Systems up to 66kV.

Key Product Categories: Connectors, Joints & Terminations MV HV | Cable Preparation & Jointing Tools | Duct Seals | Cable Transits | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Clothing & Protection | Cable Pulling | Earthing & Lightning Protection | Feeder Pillars

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 & SEANEX.

Cable Cleats | Importance, How To Specify & International Standards

What Are Cable Cleats?

“A cable cleat is a device designed to secure electrical cables when installed at intervals along the length of the cables” – IEC 61914 Cable Cleats for Electrical Installations

“Cable cleats should:

Prevent excessive cable movement due to fault-current magnetic forces

Be rated for specific cable size and available current.”

The fifth edition of API Recommended Practice 14F (Design, Installation and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities).

“Single core electric cables are to be firmly fixed, using supports of strength adequate to withstand forces corresponding to the values of the peak prospective short-circuit current.” – Lloyds Register. Rules and Regulations for the Classification of Ships, Part 6, Control, Electrical, Refrigeration and Fire.

“Cables are to be installed and supported in ways to avoid chafing and undue stress in the cable.” – ABS Steel Vessel Rules 4-8-4/21.9 Cable Support, 4-8-4/21.9.1 General and 4-8-4/21.9.3 Clips, Cable Saddles, Straps

“In order to guard against the effects of electro dynamic forces developing on the occurrence of a short-circuit or earth fault, single core cables shall be firmly fixed, using supports of strength adequate to withstand the dynamic forces corresponding to the prospective fault current at that point of the installation.” DNV Rules for Ships / High Speed Light Craft and Naval Surface Craft, Pt. 4 Ch. 8 Sec.10 – page 68, C50

ALWAYS REMEMBER: Any power cable system designer or installer has an obligation to consider the method of securing cables in order to restrain their movement whether caused by an electrical fault or any other reason – a job that can only be safely and securely done with correctly specified cable cleats.

1. Calculate the system peak fault current
2. Identify the specification of the cable to be used including the nominal cable diameter and the manufacturing tolerance
3. Identify the support structure type e.g. Ladder ( including rung spacing), basket, individual steel structure etc
4. Consider support structure material type e.g. stainless steel, galvanised steel etc
5. Consider the environmental conditions
6. Consult with Ellis Patents who will provide you with the most cost effective solution for your needs

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WHAT IS THE INTERNATIONAL STANDARD FOR CABLE CLEATS?

IEC 61914 Cable cleats for electrical installations outlines a series of tests that can be used to assess the performance of a cable cleat’s design.

Although the standard does not define pass or fail levels, it allows manufacturers to define the performance characteristics of their products, and specifiers to compare products from different manufacturers.

The aspects of construction and performance covered by the standard include:

• Material type – i.e. metallic, non-metallic or composite
• Minimum and maximum declared service temperatures
• Resistance to impact at the minimum declared operating temperature
• The ability of the cable cleat to withstand axial slippage forces
• Resistance to electro-mechanical forces – i.e. the ability of the cable cleat to withstand the forces between the cables in the event of a short-circuit
• Resistance to UV and corrosion
• Flame propagation

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TRANSPORT FOR LONDON PROJECT

Working with Ellis Patents we completed the specification and have now moved into manufacturing for our largest contract to date to supply TfL (London Underground) approved cable hangers across several depot modernisation projects.

Thorne & Derrick in consultation with the Asset Manager at Transport for London and their appointed Telecoms & Power contractor secured formal Authorisation & Approval for the Pegasus range of non-metallic cable support hangers. The product will provide safe cable management of the cable route within the Bridges & Structures category – over 1000 hangers with proven lifecycle performance and utilising the standard J-type design for support of multiple cable runs including single, 3-way and 5-way configurations are now scheduled for delivery.

Thorne & Derrick are Approved Vendors to both Network Rail and Transport for London

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THORNE & DERRICK

Thorne & Derrick are national distributors of LV, MV & HV Cable Installation, Jointing, Substation & Electrical Equipment – servicing businesses involved in cabling, jointing, substation, earthing, overhead line and electrical construction at LV, 11kV, 33kV, 66kV and EHV. Supplying a complete range of power cable accessories to support the installation and maintenance of low/medium and high voltage power systems:

• Slip-on Cable Terminations
• Cold-shrink Cable Terminations
• Heat-shrink Cable Terminations
• Cable Joints – Heat & Cold-shrink
• Separable Connectors (Euromold)
• Surge Arresters & Switchgear/Transformer Bushings

Key Product Categories: Duct Seals | Cable Cleats | Cable Glands | Electrical Safety | Arc Flash Protection | Cable Jointing Tools | Cable Pulling | Earthing | Feeder Pillars | Cable Joints LV | Joints & Terminations MV