Thorne & Derrick | Connectors Distributed from Stock | UK & Export Sales
The technology of shearbolt connectors for current transmission has developed quickly – the principle of shearbolt technology was first introduced in the early 1980s when manufacturers sold the first types of low voltage LV bolted connectors. The next step was adopting shearbolt technology for use in low voltage cable applications, where required torque moment was a pre-set parameter machined into the bolt. Based on positive field experience, shearbolt connector technology was adapted for use in medium voltage applications as well. But cable accessories up to 42kV require concentric connector bodies and smooth outer surface, without sheared off bolts standing proud and no sharp edges at the connector and bolts.
In the 1990s, connector manufacturers introduced different types of multiple shear bolts, allowing a requested torque moment to a particular cable cross-section while ensuring that bolts shear off flat with the outer circumference of the connector body. At the same time, IEC 601238-1 was established to replace former local standards and set higher requirements in terms of contact ageing. The most important advantage of bolted contacts is that one connector type applies for different cross-sections and conductor materials. This created a user-friendly and reliable connector, simplifying allocation of conductor cross-section to connector. Those same principles and connector body design have been adapted and optimized to cover cross-sections of up to 3000sqmm and even for HV/EHV applications.
By Fak Hardt
Head of Product Portfolio & Cable Accessory Development, Pfisterer Holding, Germany
Mr. Hardt is an Electrical Engineering professional.
He has had more than 24 years of experience in manufacturing as R&D-Manager for connectors and fittings with Pfisterer as well as in development of underground power cables and accessories. He has in-depth knowledge of related production processes, quality and environmental management and holds patents for bolted technology and ring connector technology. Pfisterer is a leading independent manufacturer of cable, connectors, insulators and overhead line accessories for sensitive interfaces in energy networks. The Group is headquartered in Winterbach, near Stuttgart in southern Germany.
Pfisterer Sicon | Shearbolt Connectors
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 voltage power systems:
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 HVÂ
Cable Innovation Tools & Accessories for Low & High Voltage Power Systems
Joints Terminations Connectors | Stock Service Support from Thorne & Derrick
Special thanks to Andy Chaluda Business Development Manager - Technical Services at AN Wallis
Earth Electrode Systems are a critical part of any electrical system, yet are often seen as inert and may sometimes be dismissed as cost-saving or forgotten about until a later stage of the project. But should these earthing systems by AN Wallis fail due to incompetent design or the use of cheap substandard earthing components, the resulting events may be catastrophic to infrastructure or even lethal to people.
Our team of highly experienced professional Engineers & Technicians use the world’s most up to date Electrical Earthing Analysis software package CDEGS to assist in the earth electrode system design process. CDEGS is now recognised as the industry standard earthing design analysis software in the UK and in many other parts of the world.
Our Earth Electrode System Designs not only comply with the relevant National and International Standards, but also follow the ethos of the UK Governments’ Construction, Design & Management (CDM) Regulations 2015.
Some of the areas we are working in are:-
The most powerful and accurate suite of commercially available grounding (earthing) and electromagnetic analysis software packages on the market. A complete array of auxiliary software tools are included in the CDEGS suite to complement, support and enhance the methods used to solve various problems involving grounding, electromagnetic interference, electromagnetic fields and transient phenomena that can be tackled by CDEGS.
The 3 areas to analyse with any Earth Electrode system are the Touch, Step and Rise of Earth Potentials (RoEP) also known as Earth Potential Rise (EPR or Ground Potential Rise (GPR).
We will liaise with the DNO or Electricity Supply Company on your behalf to gain all the required ‘Point of Connection’ data for your new electrical connection.
Using the Soil Resistivity data, we produce a conceptual earth electrode system layout based on your existing plant layout drawings and analyse the associated voltage contours using either the MALT or MALZ module of the CDEGS software.
Graphical plots are produced using the CDEGS software that visually identifies any ‘hot’ spots around the site that may need further design time.
These Touch, Step and Rise of Earth Potential levels are assessed, and only when they are within safe limits will we pass this design for construction.
Further calculations will be carried out to determine whether the site may influence other electrical installations under fault conditions and from that we can determine the site ITU classification as either HOT or COLD.
Only once we have confidence that the design is parameters are met, a full ‘for construction’ style drawing will be produced.
The Wallis product range includes copper earth rods (solid copper, copper bond and stainless steel types), earth bars, copper tape, earth clamps and aluminium tapes.
Specialist Distributors: LV, MV & HV Cable Jointing, Substation & Electrical Eqpt
THORNE & DERRICK are national distributors of LV, MV & HV Cable Installation, Jointing, Duct Sealing, Earthing & Electrical Equipment – we service UK and global businesses involved in cable installations, substation, overhead line and the installation of medium/high voltage cable joints and terminations at LV, 11kV, 33kV and HV.
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.
66kV Terminations NOW Ex Stock Thorne & Derrick | 3M Electrical Cold Shrink QTEN Terminations | LV HV Cable Jointing & Electrical Equipment | contact us on 0191 4104292 | [email protected] | THORNE & DERRICK LV HV Jointing, Earthing, Substation & Electrical Eqpt to the Renewables & Power Industry | View 3M Electrical Products and contact us with your enquiry.
Thorne & Derrick are Specialist Distributors to the UK and international Offshore Wind & Renewable industry to provide safe and reliable
LV HV Electrical Cable & Power Distribution Systems up to 66kV – we are highly customer responsive and absolutely committed to providing a world-class service.
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 HVÂ
See how T&D support, supply and service the Renewable Energy industry.
Thorne & Derrick are Approved Distributors for Roxtec, the leading manufacturer of sealing solutions for cables and pipes, to protect electricity Transmission & Distribution assets including windfarm substations against water ingress, gas migration and fire hazards.
In this 2 part article series Roxtec provide an overview of sealing cables in LV MV HV applications for offshore and onshore substations and to help understand and learn about the importance of of sealing cable entry points and cable ducts.
Thorne & Derrick are Specialist Distributors to the UK and international Offshore Wind & Renewable industry to provide safe and reliable
LV HV Electrical Cable & Power Distribution Systems up to 66kV – we are highly customer responsive and absolutely committed to providing a world-class service.
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 HVÂ
See how T&D support, supply and service the Renewable Energy industry.
MV HV Cables 11kV 33kV 66kV | Cable Joints, Terminations & Connections
Sealing Pipes & Cables
Onshore Windfarm Substations, Enclosures & Foundation
Roxtec provides offshore wind farms with an “all in one” solution for cable entry sealing, cable management and vibration damping. Standardise with Roxtec seals for efficient offshore windfarm cable protection design, quick roll-out and certified protection – cables are securely fixed, sealed and cable lifetime is extended.
An overview of sealing cables in LV MV HV onshore windfarm, cabinets & enclosures, kiosks and foundation based upon industry standards and practical experience – see the Roxtec range of sealing products suited to the application below and the importance of sealing cable entry points and cable ducts.
Thorne & Derrick are distributors for Roxtec, the leading manufacturer of sealing solutions for cables and pipes, to protect electricity Transmission & Distribution assets including substations against the potential catastrophic effects water, gas and fire.
 Also: Sealing Cables In Onshore Substations – A Roxtec CPD
Sealing Cables In Onshore Substations
Roxtec have 5 application areas within the Onshore Wind Industry where there are great benefits from using their solutions:
Roxtec multi-cable entry seals are ideal for control cabinets, junction boxes and other electrical and instrumentation enclosures. By using our seals, you can handle high cable density and reduce the size and weight of the cabinets. Save time and labour with sealing solutions prepared for last minute changes.
Why use Roxtec?
Superior Simplicity
Roxtec seals work efficiently in underground walls. Specify them with their knock-out sleeve to seal openings until cable routing. Avoid water, humidity and rodent issues in your turbine foundations.
Why use Roxtec?
Superior Simplicity
Roxtec seals work efficiently in underground walls. Specify them with their knock-out sleeve to seal openings until cable routing. Avoid water, humidity and rodent issues in your kiosks. Roxtec seals take the load off the cables and eliminate the cable bending issue.
Why use Roxtec?
Superior Simplicity
Roxtec Knock-Out Sleeve
Roxtec seals work efficiently in underground walls. Specify them with their knock-out sleeve to seal openings until cable routing. Avoid water, humidity and rodent issues in your collector stations. Roxtec seals take the load off the cables and eliminate the cable bending issue.
Why use Roxtec?
Superior Simplicity
Roxtec seals work efficiently in underground walls. Specify them with their knock-out sleeve to seal openings until cable routing. Avoid water, humidity and rodent issues in your landing stations. Roxtec seals take the load off the cables and eliminate the cable bending issue. Fulfill EMC requirements with our EMC solutions for bonding, grounding and electromagnetic shielding.
Why use Roxtec?
Superior Simplicity
Seals for underground use – Use Roxtec UG™ solutions where cables and pipes enter basements in order to eliminate the risk of rodents, flooding and partial discharge.
Roxtec | Lillgrund in Sweden is one of the largest offshore wind farms in the world generating green energy to 60,000 households with cables sealed and protected by Roxtec
Cable Transits – Sealing Cables & Pipes
Thorne & Derrick are Specialist Distributors to the UK and international Offshore Wind & Renewable industry to provide safe and reliable LV HV Electrical Cable & Power Distribution Systems up to 66kV – we are highly customer responsive and absolutely committed to providing a world-class service.
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 HVÂ
See how T&D support, supply and service the Renewable Energy industry.
MV HV Cables 11kV 33kV 66kV | Cable Joints, Terminations & Connections
MV HV Cables 11kV 33kV 66kV | Cable Joints, Terminations & Connections
Published 18 Mar 2026
INDUSTRIAL LABEL PRINTING SOLUTIONS When clear, durable and professional identification is required across control panels, cable systems, production facilities and industrial installations, print quality, reliability and ease of use are critical. Cembre industrial label printers are designed to support...
Published 18 Mar 2026
HIGH VOLTAGE JUNCTION BOXES & ENCLOSURES When high-voltage power distribution and cable termination are required, safety, enclosure integrity and long-term reliability are critical. HV Junction Boxes and Electrical Enclosures manufactured by Abtech are engineered for the safe distribution, cable termination and protection...
