Challenge | This week a Solar EPC client of Thorne & Derrick engaged our Technical Sales Department to assist with ongoing O&M issues relating to the termination connection of steel wire armour (SWA) on 450off 4 core x 240sqmm LV AC cables, 0.6/1kV – the outdoor location cables are connected to a string inverter and the MV station at the remote end on a UK based 50MW solar farm in Derbyshire. The cable armouring provides mechanical protection but is not intended to circulate electrical current.
SWA Cable Steel Wire Armoured Cables | Image FS Cables
BS7671 Clause 522.8.10
“Except where installed in a conduit or duct which provides equivalent protection against mechanical damage, a cable buried in the ground shall incorporate an earthed armour or metal sheath or both, suitable for use as a protective conductor. The location of buried cables shall be marked by cable covers or a suitable marker tape. Buried conduits and ducts shall be suitably identified. Buried cables, conduits and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground.”
Solution
Initially, from the viewpoint of the above British Standard the client considered connecting the wire armour at the MV station to ensure that during a fault (e.g.cable strike) an earth path exists to allow safe disconnection of the cable. Earthing the armours of buried SWA cables is important for safety – this prevents/reduces the severity of electric shocks and equipment damage should a person dig inadvertently into the cable. The cable wire armours provide a complete earth path around the cable. Utilizing a single phase within a 4 core cable as earth is not sufficient as it does not offer complete protection around the circumference of the cable. Also, in solar farm installations un-earthed wire armours can have induced voltage from excessive current generated. Therefore, the contractor should always consult the circuit designer.
Customer Service
From initial application, to concept, to design and to sample acceptance by the end client we subsequently completed the despatch and delivery of their order in 5 working days for 450off Armour Earthing Kits.
Important Note
Solderless earth kits that are intended for copper tape screens (MV cables) are a substandard method to earth SWA cables. Solderless earth kits utilize a constant force spring which do not offer a secure earth bond for SWA’s. Also, the cross sectional area of the braid within these kits is inadequate which is why you should always use an armour earth kit for this application. Contact us to discuss your application.
Innovative Connection & Grounding Solutions for LV Cables
Excerpt from Installation Instruction
Heat Shrink Outdoor Armour Earth Kit To Suit
XLPE SWA PVC
The Heat Shrink Outdoor Armour Earth Kit includes medium wall adhesive lined heat shrink tubes, mastic tapes, solder-blocked earth braids and clamps. Contact us for further information, technical support or for a quotation.
THORNE & DERRICK are Specialist Distributors of LV HV Solar Cable Accessories, Jointing, Termination, Earthing & Electrical Equipment 1500V DC to 33kV – we service UK and global businesses involved in cable installations, jointing, substation and electrical construction.
Since 1985, T&D have established reputation based on SERVICE | INTEGRITY | TRUST – we are highly customer responsive and absolutely committed to providing a world-class service.
We provide expert technical support and supply from a multi-million pound stock holding:
Further Reading
Thorne & Derrick are Specialist Distributors of Innovation Tooling & Accessories for LV HV Power Systems to facilitate safe and reliable cutting, crimping, preparation, termination and installation of cables, 600V to 132kV.
Press Release | 26.1.2024
Thorne & Derrick, the Specialist Distributor of LV HV Cable Accessories, Tooling & Substation Equipment, are delighted to announce a Partnership Agreement with Horizon Utility Supplies Ltd, one of the largest suppliers of Tools & Equipment to the UK DNO’s.
“Our Partnership Agreement is focussed on the introduction of the Vicera APU2.0 Cable Jointers Stand to the UK DNO’s and National Grid. Initial interest and sales uptake has been outstanding with immediate acceptance by several utility clients of Horizon and field trials ongoing with others. The APU2.0 is now available from stock at Horizon – please do hesitate contact them for further information, site demonstration or sales enquiries.”
“Thorne & Derrick introduced the Vicera range into the UK early last year and the product has been adopted by many High Voltage Power Contractors, ICP’s, Cable & Accessory Manufacturers including Nexans, 3M, Hellenic, NKT, Tyco and Pfisterer. Working alongside the team at Horizon we look forward to improving cable safety and working practices within the UK DNO’s,” comments Chris Dodds (Thorne & Derrick Sales & Marketing Manager).
“Horizon Utility Supplies are excited to announce our partnership with Thorne & Derrick, for promoting the Vicera APU2.0 Cable Jointer Stand into the major utilities in the Electricity Supply Industry. This collaboration allows us to use the strengths of both companies to deliver workplace solutions to our customers and reflects our shared dedication to meet the evolving needs of our industry.”
“The Vicera range of products offers a great opportunity to kick-start our Partnership, fitting perfectly into our portfolio of products for the supply of equipment for the care and maintenance of the utility network within UK DNO’s. We are very much looking forward to working with our partners at Thorne & Derrick,” comments Richard Casey (Horizon Utility Supplies, Managing Director).
APU2.0 | Cable Stability & Support for MV HV Cable Jointing & Termination
The Vicera APU2.0 Jointers Stand for both field or training centre use provides safe and stable support of Low, Medium & High Voltage Cables – the cable stands are suitable for cable diameters 18-90mm with adjustable height for substation, joint bays or trench use.
The Cable Joint Stands feature step-less lateral and tilt adjustment and high strength clamps to prevent cable slippage or movement while jointing – secure and balanced cables when Jointers are undertaking highly skill-sensitive cable preparation prevents inadvertent damage to cables and future potential O&M reliability.
The cable support stands are rugged and durable for outdoor use in joint bays and trenches in all ground terrain conditions – this includes the support of 11kV/33kV/66kV cables to enable precise cable preparation by the Jointer prior to installation of joints, terminations or connectors on medium/high voltage power cables.
Stability & Security of Power Cables
Horizon Utility Suppliers were established in 1996 specialising in the distribution of equipment and PPE for working live on overhead power lines and underground cables – Horizon hold a reputation for engineering custom-solutions to provide problem solving and innovative products for Linesmen, Jointers, Substation Fitters & Utility Engineers.
Tel: +44 (0)1275 342700 | [email protected]
LV HV | Cable Jointing, Termination, Substation & Electrical Eqpt 600V to 66kV
Earlier today at PFISTERER Sheffield the Thorne & Derrick Team benefitted incredibly from a Practical Training Day covering the benefits, specification and installation of CONNEX & SICON brands of MV Cable Accessories. The world-class standard of Cable Preparation Skills demonstrated by Dan & Jon using PENTA FRANCE (Alroc) & Ripley Tools assists our ability to provide technical support to customers.
Commercially, we are now further increasing both the levels and extending the lines of our PFISTERER stocks at Thorne & Derrick.
Thanks so much to Daniel Leech, Jon Reed, Mark Hanlon, Bethany Dodson, Tracey Stevenson, Cathy Longstone & Paul Tuckwood.
THORNE & DERRICK LV-HV Cable Accessories, Jointing, Tooling, Substation & Electrical Safety Eqpt | Approved PFISTERER UK Stockists.
PFISTERER with Thorne & Derrick
Ripley US02 Tool – The “Red Ripley”
Pfisterer Cable Training School for Jointers
Alroc CWB – The “Blue Tool”
Stripping MV Medium Voltage Cables 33kV
MV HV Cable Jointers Tools Sets
Supporting Cables Using Vicera Jointers Stands for MV HV Cables
Thorne & Derrick | Distributed from Stock | Approved Supplier | UK & Export Sales
During our monthly Distributor Review Meeting this morning with Kate Palmer-Randle we discussed further developing the Qualified Electrical Construction Contractor Accreditation (QECC) from 3M Electrical in the UK.
The Qualified Electrical Construction Contractor Programme (QECC) has been set up as a partnership designed to provide valuable benefits to appointed 3M Electrical Contractor Partners.
As part of the QECC programme, contractors receive in-depth 3M product and technology training, including theoretical training on 11kV, 22kV, 33kV, 52kV & 66kV Cable Accessories, including Joints & Terminations.
Once Certified the QECC contractor can apply for a 3M 20-year MV Product Warranty) on completed projects which can be passed on to their client to offer them peace of mind on their investments and evidence Competency.
To date four companies have been geographically appointed, with a select number of new members set to qualify over the coming months.
Choosing a 3M QECC certificated company allows you to have peace of mind that the contractors you’re working with are trained to the highest level and backed by an extended 3M 20-year product warranty.
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.
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 medium/high voltages.
Thorne & Derrick hold large stocks of 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.
THE SEMICON SCREEN
THE MOST CRITICAL POINT IN ANY MV CABLE JOINT, TERMINATION OR CONNECTOR
In this Article you can read about The F-Word, Jointer Competency, “Pick-off”, Bevelling, PD, Semicon Perfection, Circumferential Grooving, Delamination, “Cut-back” and how appropriate tools from ALROC and Ripley Tools available from Thorne & Derrick | LV HV Cable Jointing & Electrical Equipment create resilient MV Power Systems.
Thorne & Derrick
MV HV High Voltage Cable Joints | Cable Terminations | Cable Connectors | Distributed from Stock | UK & Export Sales
The Semicon Screen – The Most Critical Point In Any MV Cable Joint, Termination Or Connector
Cable Innovation Tools & Accessories for Low & High Voltage Power Systems | THORNE & DERRICK are Specialist Distributors of LV HV Cable Jointing, Earthing, Substation & Electrical Eqpt up to 66kV – this includes the most extensive range of Ex Stock Innovation Tooling to facilitate safe and reliable preparation, termination and installation of cables.
Published 15 Oct 2025
Testimonial Organiser | EA Technology Event | Industrial Forum 2025 Title | Keeping Electrical Switchgear Safe Date | 14th October Location | Chester Racecourse By | Chris Dodds (Sales & Marketing Manager at Thorne & Derrick | Co-Exhibitor with...
Published 18 Sep 2025
Thorne & Derrick International, the UK’s leading Specialist Distributor of LV HV Cable Accessories, Tooling & Hazardous Area Electrical Equipment, are celebrating 40 years of supplying products and solutions that ensure the safety and reliability of industrial heating, lighting...
