In order to safely and professionally prepare medium/high voltage cables a complete set of cable jointing tools are required to enable the stripping and removal of the 11kV triplex cable sheath, insulation and screen – this includes Alroc tools used by jointers for MV/HV cable preparation and Cembre tools to cleanly cut and crimp cables.
The jointers have used cable cleaning wipes to carefully remove debris, dust or contaminants from the Triplex cables to ensure the overall reliability of the 11kV heat shrink cable terminations.
Lucy Switchgear
11kV cables are shown terminated using heat shrink terminations into Lucy VRN2a SF6 Ring Main Unit with a 200A Circuit Breaker to UKPN specification – the Sabre range of RMU’s manufactured by Lucy Switchgear are non extensible ring main units for outdoor high voltage substations. Along with low voltage distribution cabinets, these RMU’s can be easily coupled to the distribution transformer forming a compact outdoor package substation.
The 11kV heat shrink terminations are crimped using mechanical shearbolt cable lugs and bolted to the interface bushings of the air insulated cable box.
Here, the 11kV Triplex cables are shown terminated into a high voltage cable termination box using 3M Cold Shrink terminations – the concertina style bushing boot is cold-applied and suitable for both straight or right-angled 11kV switchgear connections, part code 3M 92EE717-1.
The bushing boots insulate the cable lug connection onto the bushing interface located on the electrical equipment. The Triplex copper wire screens are shown bonded to earth using brass mechanical shearbolt cable lugs.
The unarmoured Triplex cables are provided with mechanical cable retention and moisture ingress protection using heat shrink cable glands – the glands provide a watertight and fume-tight cable seal where the Triplex cables enter high voltage connection boxes, switchgear, bulkheads, or other enclosures.
The HV cables are cable ducted within the hot zone and a stand-off insulator is mounted in each HV cable box. The cable sheath is shown terminated to an earth bar mounted onto the stand-off insulator.
Image: NPG Northern Powergrid
Triplex Cable Sheath Earthing Arrangement 11kV
Should you require any assistance with the selection or specification of 11kV triplex cables or 11kV cable lugs please do not hesitate to contact us.
♦ Also 11kV : Nexans Connectors | Pfisterer Plugs | 3M Joints & Terminations | Ellis Cable Cleats | Duct Seals
LV ♦ MV ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Installation & Cable Pulling Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
T&D’s Power Blog covers: LV MV HV & EHV Transmission & Distribution, Substations, Switchgear, Cable Jointing & Termination, Cable Fault & Repair, Underground Cables.
➡ Visit Power Blog.
by Chris Dodds - Sales & Marketing Manager Thorne & Derrick
Prior to jointing cables in confined spaces control measures and risk assessment must be undertaken. This picture was taken from outside the manhole once the cable joint was complete – the looped cables were spliced using 3M Scotchcast cable joints to effect a repair to damaged cables in a confined space.
Initially the cable jointers bump test their gas detectors then gas sample the manhole with the lid on for the presence of harmful, flammable or toxic gas.
If all is safe to proceed the jointers remove the lid. Next the working space is vented with forced air while the jointers constantly monitor the confined space with their gas detectors. Access to the manhole is via a wooden ladder with the cable jointers wearing a rescue harness – a tripod and winch are positioned and a gate guard around the manhole is erected to prevent trips, falls or accidents.
The cable is jointed within the manhole to prevent overbending strains on the low voltage cable when fed back into the manhole if jointed at ground level – cable duct seals can be used to prevent the migration of flammable gas or flood waters into the manhole.
The 500kcmil 100 volt rated DC cable circuit is operating at 600 volt – the cable joint/splice utilises 3M Scotch Electrical Tapes with no heat shrink or cold shrink tubing.
3M Scotchcast Cable Joint – Resin & Taped Manhole Cable Splice 600/1000V
3M cable joints use Scotchcast resins for the low voltage jointing of cables with XLPE, EPR, PVC or PILC insulation up to 3.3kV. Resin cable joints specially modified with high performance hydrocarbon resistant, low smoke zero halogen, fire resistant and flame retardant resins are available to withstand harsh operating and environmental conditions in industrial and hazardous area locations. The 3M cable joints are specified throughout ther oil, petrochemical, gas, mines, telecoms, rail and industrial cables are available – suitable for direct burial (underground) or exposed onto cable containment.
Resin Cable Joints – Features & Benefits Of 3M Scotchcast Cable Jointing Systems
Contact Thorne & Derrick to discuss your application for jointing LV cables – we can provide expert technical support, training and specification advice to ensure the correct supply of electrical LV cable joints to suit industrial and hazardous area location cables.
T&D – Main Distributors For 3M Electrical
Should you require any assistance with the selection or specification of cable joints or terminations using 3M Cold Shrink on MV-HV cables please do not hesitate to contact us.
LV ♦ MV ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Installation & Cable Pulling Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
T&D’s Power Blog covers: LV MV HV & EHV Transmission & Distribution, Substations, Switchgear, Cable Jointing & Termination, Cable Fault & Repair, Underground Cables.
➡ Visit Power Blog
Electrical Safety Equipment | Insulating Gloves | Arc Flash Gloves
uploaded by Chris Dodds - Thorne & Derrick Sales & Marketing Manager
There are a lot of misconceptions about arc flash clothing and protection levels required including what actually is a flash of light or an arc of fire. Similar to an electric shock but not the same as usually there is not direct contact with electricity.
Arc flash is a serious issue with more than 30,000 incidents that result in 400 fatalities every year. So how can you protect your hands from this deadly killer and do insulating gloves provide arc flash protection? Or are special application arc flash gloves required?
The below Blog from Scanwear delves deeper into the issue.
One question that comes up all the time during electrical safety training is whether or not an electrician’s rubber insulating gloves offer any protection from Arc Flash?
Interestingly enough, even though you probably won’t find a label on the insulating glove that says so, rubber insulating gloves used in conjunction with leather protectors do offer sufficient protection from arc flash burns.
Now we are talking about arc flash protection but don’t forget why you are wearing the gloves in the first place. That needs to be your primary concern when it comes to protecting your hands. Once you’ve got that taken care of you can worry about arc flash.
Is This Legitimate?
The industry standard for electrical safety, NFPA70E, does not offer much information about how to size your gloves for arc flash protection or how to determine the incident energy rating for your gloves but we are led to believe that they have done some testing and feel comfortable saying that the rubber insulating gloves with leather protectors will protect you from an arc flash.
Here is what it says in the standard:
“If rubber insulating gloves with leather protectors are used, additional leather or arc-rated gloves shall not be required. The combination of rubber insulating gloves with leather protectors satisfies the arc flash protection requirement.”
That note applies to an arc flash PPE category of 4 which requires a minimum of 40 cal/cm2 protection. So that gives the user a good level of comfort that the gloves offer great protection from arc flash.
How Can You Prove It?
Up until June 2013, the amount of arc flash protection was determined by the thickness of the leather protectors. That year though a new standard for testing gloves was approved and testing started immediately. Because thickness of the gloves was not part of the criteria for meeting the standard manufacturers are now coming out with thinner leather gloves that still offer the maximum protection against arc flash.
Something you might want to look into with your supplier of arc flash clothing, garments and protection including helmets and gloves.
Also, traditional rubber insulating gloves with leather protectors were tested alongside some of the arc flash gloves which you may now see on the market and it was proven that they offer fantastic protection from arc flash. In case you are curious, the standard for testing gloves for arc flash is ASTM F2675-13.
Just remember, the main reason you are wearing the rubber insulating gloves is to protect against shock hazards. Fortunately, your regular rubber insulating gloves with leather protectors offer an excellent protection from an arc flash hazard and should always be worn, when there is a risk of a shock or an arc flash event.
Further Information ➡
Arc Flash Gloves | 25 40 60 Cal Arc Flash Protection Gloves PPE
Arc Flash Gloves | 50 Cal Arc Flash Protection Gloves PPE
Selection Of Correct Gloves
Insulating gloves should be selected according to their class which corresponds to the voltage level used – additionally the gloves are classified into categories according to environmental resistance properties detailed below.
When selecting the correct insulating gloves all of the above factors are vital to consider in order to achieve the adequate level of protection required.
In addition, some gloves will also require an under-glove for comfort or a leather over-glove to maintain product longevity.
Inspection and storage of insulating gloves is also a vital factor to consider as all gloves must be visibly inspected after each inflation and before each use.
This is to make sure there are no tears or abrasion to the gloves prior to use, maintaining their dielectric properties.
Insulating rubber gloves are also categorised by environmental resistance properties for protection against acid, oil, o-zone and very low temperatures.
The following gloves manufactured by CATU Electrical and T&D would normally recommend for mechanical protection they be used with silicon leather glove covers or over-gloves but in light of the above this might all change.
| Insulating Gloves Class | CATU Electrical Code | Category | Thickness | Length | Colour | AC | kV | DC |
| Class 00 | CATU CG-05 | AZC | 0.5mm | 360mm | Beige | ≤ 500V | 0.5kV | 750V |
| Class 0 | CATU CG-10 | AZC | 1mm | 360mm | Beige | ≤ 1000V | 1kV | 1500V |
| Class 1 | CATU CG-1 | RC | 1.5mm | 360mm | Bi-Colour | ≤ 7500V | 7.5kV | 11,250V |
| Class 2 | CATU CG-2 | RC | 2.3mm | 360mm | Bi-Colour | ≤ 17000V | 17.5kV | 25,500V |
| Class 3 | CATU CG-3 | RC | 2.9mm | 360mm | Bi-Colour | ≤ 26500V | 26.5kV | 39,750V |
| Class 4 | CATU CG-4 | RC | 3.6mm | 410mm | Bi-Colour | ≤ 36000V | 36kV | 54,000V |
Thorne and Derrick are proud to be distributors of ProGARM arc flash coveralls and protection.
We can help – should you require arc flash calculators or advice on the type of clothing and protection available please do not hesitate to contact us.
We supply 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
Nexans Euromold screened separable connectors are used to terminate high voltage cables with polymeric insulation (XLPE & EPR) onto switchgear and transformer bushings up to 11kV-33kV.
Screened separable connectors are also known as screened elbow connectors or tee connectors.
The HV cable connectors suit high voltage electrical equipment and are compatible with gas insulated switchgear (GIS) manufactured by ABB, Siemens, Alstom, Brush and Hawker Siddley.
Euromold bushings are also available for other types of high voltage oil, air and gas insulated switchgear and transformers to CENELEC EN50180 and ANSI IEEE 386 standards.
Here the Euromold connectors are shown terminating single core 11kV EPR insulated cables with copper wire screens onto switchgear bushings – the wire screens are bundled collectively and earthed onto the copper busbar using brass mechanical cable lugs.
The 11kV cable conductors have been terminated by the cable jointer and crimped using copper cable lugs, possibly bi-metallic type. The cable conductors could be aluminium suggested by the visible reflection due to the flash inside the Nexans tee connector body. An insulating plug will go into the gap closing the air gap to the outside of the Nexans connector semi-conducting layer. When selecting high voltage cable lugs for stranded copper 11kV-33kV conductors it is crucial to ensure crimp lugs are manufactured using high conductivity copper usually in accordance with BS EN 12735-1:2016 and with a material purity of 99.5%, typically the Cembre 2A range.
Compatible with heat shrink and cold shrink terminations, Cembre 2A cable lugs are also watertight without inspection holes and feature extended barrels to achieve optimum HV cable termination of the conductor without risk of burning-out due to sub-standard crimp connections – cable lugs are available electrolytically tin-plated to BS1872 standard for high corrosion and humidity installations within 11kV/33kV substations.
The range of Nexans MV HV power cable joints, terminations and connectors can be used on applications at 6.6kV, 11kV, 15kV, 24kV and 33kV.
See more Nexans Cable Terminations:
Should you require any assistance with the selection or specification of Euromold separable connectors or bushing types please do not hesitate to contact us.
LV ♦ MV ♦ HV
T&D distribute the most extensive range of LV, MV & HV Cable Jointing, Terminating, Installation & Cable Pulling Equipment – we service UK and international clients working on underground cables, overhead lines, substations and electrical construction at LV, 11kV, 33kV and EHV transmission and distribution voltages.
LV – Low Voltage Cable Joints, Glands, Cleats, Lugs & Accessories (1000 Volts)
MV HV – Medium & High Voltage Cable Joints, Terminations & Connectors (11kV 33kV EHV)
Cable Laying – Underground Cable Covers, Ducting, Seals & Cable Pulling Equipment
T&D’s Power Blog covers: LV MV HV & EHV Transmission & Distribution, Substations, Switchgear, Cable Jointing & Termination, Cable Fault & Repair, Underground Cables
➡ Visit Power Blog.
Marine Offshore Cables & Accessories – Fire Resistant Cables
➡ See also: Cable Glands | Hazardous Area Flameproof & Explosion Proof
| Helkama Cables Part Number | Instrumentation Cable Description | Cable Type |
| RFA-FRHF | Fire resistant, collectively screened instrumentation and communication cable with SHF1 or SHF2 sheath for fixed installation 250V FRHF |  |
| RFA-FRHF(i) | Fire resistant, pair- and collectively screened instrumentation and communication cable with SHF1 or SHF2 sheath 250V FRHF |  |
| RFE-FRHF | Fire resistant, armoured instrumentation and communication cable with SHF1 or SHF2 sheath 250V FRHF |  |
| RFE-FRHF(i) | Fire resistant, pair screened, armoured instrumentation and communication cable with SHF1 or SHF2 sheath 250V FRHF |  |
| RFE-EMC-FRHF | Fire resistant, armoured instrumentation and communication cable with improved EMC screening and SHF1 or SHF2 sheath 250V EMC-FRHF |  |
| RFE-EMC-FRHF(i) | Fire resistant, pair screened, armoured instrumentation and communication cable with improved EMC screening and SHF1 or SHF2 sheath 250V EMC-FRHF |  |
| LKM-FRHF | Fire resistant, unarmoured control and instrumentation cable with SHF1 or SHF2 sheath 250V FRHF |  |
| LKAM-FRHF | Fire resistant, screened control and instrumentation cable with SHF1 or SHF2 sheath 250V FRHF |  |
| LKSM-FRHF | Fire resistant, armoured control and instrumentation cable with SHF1 or SHF2 sheath 250V FRHF |  |
| LKM-FRHF | Fire resistant, unarmoured control and power cable with SHF1 or SHF2 sheath 0,6/1kV FRHF |  |
| LKAM-FRHF | Fire resistant, screened control and power cable with SHF1 or SHF2 sheath 0,6/1kV FRHF |  |
| LKSM-FRHF | Fire resistant, armoured control and power cable with SHF1 or SHF2 sheath 0,6/1kV FRHF |  |
| LKMM-FRHF | Fire resistant, unarmoured control and power cable with extruded filler and SHF1 or SHF2 sheath 0,6/1kV FRHF |  |
| LKMSM-FRHF | Fire resistant, armoured control and power cable with soft extruded filler and SHF1 or SHF2 sheath 0,6/1kV FRHF |  |
| LKSM-EMC-FRHF | Fire resistant, armoured power and control cable with improved EMC screening and SHF1 or SHF2 sheath 0,6/1kV EMC-FRHF |  |
Developing & Manufacturing Offshore & Marine Cables For Over 50 Years
THORNE & DERRICK are international distributors of LV, MV & HV Offshore & Marine Cable Installation, Jointing, Substation, Earthing & Electrical Equipment – we supply Joints, Glands, Cleats & Cable Accessories specified for use in harsh and hazardous areas to support the installation of marine and offshore fire resistant cables.
Since 1985, T&D have established an international reputation based on SERVICE | INTEGRITY | TRUST.
DNV is a rigorous approval system for cable accessories including joints, glands and cleats – the DNV approval process assesses all of the evidence offered by the manufacturer and compares it to the requirements of the international standard, IEC61914. Once full compliance is proven DNV Type Approval is offered.
DNV Approved
Hydrocarbon Resistant | Zero Halogen & Fire Resistant
Hazardous Area Explosion Proof | Zero Halogen
Zero Halogen | Fire Resistant | Stainless Steel
Also ➡ Cable Labels, Cable Ties, Cable Transits and Cold Shrink
Contact Thorne & Derrick for further information and customer service – extensive range of DNV Approved Marine & Offshore Cables & Cable Accessories available for delivery to UK and international projects.
LV MV HV – 3.3kV 6.6kV 11kV 33kV
T&D ⇒ CABLE ♦ JOINT ♦ TERMINATE ♦ CONNECT ♦ GLAND ♦ CLEAT ♦ CRIMP ♦ DUCT ♦ SEAL ♦ REPAIR
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.
Specialists Distributors of Cable Sealing Systems from leading manufacturers including: Hauff Technik | Roxtec | CSD | Filoseal
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
Published 02 Sep 2026
Celebrating Charlie & Ella’s Level 4 Sales Executive Apprenticeships At Thorne & Derrick International, we are proud to champion talent development and recognise the dedication required to achieve professional growth. We are therefore delighted to congratulate Charlie Baines and...
Published 11 Aug 2026
Thorne & Derrick will be Exhibiting at Solar & Storage Live UK 2026 at the NEC Birmingham from 22nd–24th September, showcasing our support for HV Cable Accessories, Joints, Terminations, Separable Connectors, Cable Tooling and Grid Connection Products used across...
