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Duct Sealing Solutions with Filoform

How Do I Select a Duct Sealing Solution?

At Thorne & Derrick, we pride ourselves on working with industry leaders to deliver innovative, reliable, and compliant solutions to our customers. In this edition of Ask the Experts, Ian Joynson, Technical Specialist at Filoform, talks all things duct sealing — from common challenges in the field to the importance of long-term protection.

Filoform’s Ian Joynson shares expert guidance on what to consider when selecting the right duct sealing solution:

“Selection should start by understanding the specific application and what the seal needs to achieve. Consider:

➖ Are there cables present, and how many?
➖ Is water ingress an issue? If so, how much?
➖ Is fire protection required?
➖ Does the duct enter a building?
➖ Are gases or chemicals a concern?

The right solution should be chosen during the design phase, where sealing requirements can be aligned with the overall project scope.

Most specifications will demand resistance to water, gas, and sometimes fire or chemicals. Expected seal life is also critical — and any reputable manufacturer should be able to validate this.

Avoid over-engineering the seal design. Ultimately, a duct sealing solution that meets the specific needs of the application is the right solution.”

Thorne & Derrick is trusted distributor of Filoform duct sealing systems, supplying reliable and high-performance solutions to contractors, engineers, and project teams across the UK and internationally. Whether you’re sealing cable ducts in substations, renewable energy sites, or industrial facilities, we provide expert support and fast delivery to help you get the job done right.

Duct sealing and sealing products manufactured by Filoform, including the Filoseal range, are installed to provide gas tight and watertight sealing for cable duct entries – protecting underground cables and substation ducting infrastructure against flood and migration of flammable and toxic gas hazards. Fire resistant version also available – suitable for sealing LV-HV power, telecoms and fibre optic cables.

Filoform manufacture and supply quality products and solutions to connect, seal and protect low, medium and high voltage underground cable networks.

Thorne & Derrick provide competitive prices and fast delivery from stock for the complete range of Filoform duct seals and cable joints.

View the complete range of Filoform products.

FiloSeal+HD Duct Sealing System

From Power to Pavement: Enabling Smarter EV Feeder Pillar Solutions with Lucy Zodion

• Special thanks to Matt Page EV Business Development Manager at Lucy Zodion for the kind permission to republish.

BEYOND SPEED: FUTURE PROOFING EV INFRASTRUCTURE

As a trusted distributor of Lucy Zodion EV Feeder Pillars, Thorne & Derrick are proud to support the delivery of safe, robust, and future-ready power distribution solutions for electric vehicle charging networks.

In the article below featured in EV & Renewables Supplement, Matt Page, EV expert at Lucy Zodion, explores the critical factors beyond deployment speed that define a successful EV infrastructure rollout.

Lucy Zodion manufacture a wide range of products suitable to provide Low Voltage Electrical Power Distribution for EV charge points – from distribution network operator (DNO) accredited cut-outs and isolators for on-street chargers, to feeder pillars for electrical vehicle charging.

Lucy Zodion’s EVIS (Electric Vehicle Infrastructure Solutions) range delivers pre-wired EV feeder pillars from 100A to 630A reducing time on site and streamlining installation.

Beyond Speed: How to Future-Proof Your Infrastructure

Discover how strategic planning, scalability, and long-term resilience are key to building a charging network that’s ready for tomorrow.

Conversations around EV infrastructure often focus on speed – how quickly can a charging station be deployed, and how fast it can charge a vehicle. While speed is important, it’s not the only factor that determines success. True future-proofing means designing charging infrastructure that is resilient, scalable and adaptable to changing demands and evolving technology.

Building for growth, not just now

Many charging hubs installed today will need to evolve as EV adoption increases. The latest figures from Zapmap show there are now over 75,000 public charge points in the UK our demand is expected to grow significantly and infrastructure that isn’t designed with scalability in mind will quickly become obsolete.

For example, at InstaVolt’s Camphill Village Trust charging site, the approach to power distribution was designed with long-term scalability in mind. The specialised our Main Supply Pillars powering the site’s 160kW chargers were built to support future expansion while maintaining a minimal footprint. Taking this kind of forward-looking approach can prevent costly redesign later on

Similarly, the Isle of Man’s phased EV rollout demonstrates how strategic planning can ensure charging infrastructure is deployed with future expansion in mind. A well-planned approach to power distribution means sites can scale up as EV adoption increases without requiring extensive retrofits.

Resilience is key

Reliability is just as critical as speed. A charging hub that experiences frequent outages due to inadequate electrical protection or environmental wear will create frustration for drivers and site owners alike. Key resilience-focused features to consider include:

• Earth leakage protection and residual current protection to ensure long-term electrical safety
• Surge protection to guard against power fluctuations
• Anti-condensation heaters and service lighting to protect internal components and improve maintenance access.

Integrating these features from the outset can help prevent operational disruptions, enhancing user confidence and reducing long-term costs.

The M7 Real Estate project delivered by Source EV – a joint venture between SSE Energy Solutions and Total Energy – highlights the benefits of durable, weather-resistant power distribution. In high-usage environments, ensuring electrical protection and ease or maintenance is crucial for long-term success.

Collaboration matters

Future-proofing isn’t just about the technology – it’s about the process. The most effective EV infrastructure projects take a holistic, end-to-end approach, Considering electrical distribution, space constraints  and future adaptability from the start.

A strong example of this is the InstaVolt project, where power distribution was designed to allow flexibility for future transformer manufacturers equipment. Taking a collaborative approach with stakeholders ensures infrastructure remains adaptable to evolving industry requirements.

The road ahead

The shift to electric mobility is accelerating and infrastructure needs to keep up – not just with speed, but with smart, future-proofed design. Viewing EV infrastructure as an evolving system rather than a one-off installation can help ensure today’s investments continue to deliver value well into the future.

Incorporating scalable electrical systems, built-in resilience and cross-industry collaboration from the outset can help create charging networks that remain effective as demand and technology evolve. By planning with the long term in mind, we can ensure EV charging infrastructure stays ahead of demand, rather than struggling to catch up.

Compliance and standards

When specifying an EV feeder pillar, you need to make sure it is tested to the following standards:

• BS7671- IET Wiring Regulations – Covers the electrical installation of buildings, including the use of surge protection
• BS7671- IET Code of Practice for Electric Charging
• BS EN 61439 – Low Voltage Switchgear and Control Gear Assembly

Considering these key points will ensure that your EV feeder pillar is designed to deliver efficient and reliable power distribution for electric vehicle charging, contributing to a sustainable and greener future.

Lucy Zodion | Fortress Feeder Pillars | Pre-Wired Feeder Pillars | Street Lighting Cut-Outs | DNO Cut-Outs | Electrical Power Distribution Enclosures

How To Repair Damaged Cables Using Wraparound Cable Repair Kits

Installing Filoform cable repair kits

Integrity of the cable is of prime concern in mission-critical infrastructure.

Whether maintenance is being performed in utilities, telecommunications, or industrial power systems, damaged jacket cables significantly degrade operations and safety. Filoform Heat Shrinkable Reinforced Wrap Around Cable Jacket Repair Sleeves offer a tough, field-proven repair solution for on-site repair of cables, offering durability, environmental sealing, and mechanical protection.

Filoform Jacket Repair Sleeve

The Filoform cable repair sleeve is engineered for reliability in hostile environments. This metal-reinforced, heat-shrinkable wraparound sleeve enables fast, permanent cable jacket repair without cable movement or disconnection.

Cable Repair Product Features

• Heat-activated seal with hot melt adhesive
• Metal channel closure for mechanical reinforcement
• Extensive cable diameter compatibility
• Application for indoor and outdoor use when repairing damaged cables

Cable Repair Installation Guide

Important: Use a soft yellow flame (not pencil type). Always direct heat in the direction of shrinking and maintain a sweeping motion to avoid scorching. Begin shrinking from the centre outward. Ensure uniform shrinking and proper adhesive oozing.

Ensure performance perfection with this precise installation procedure:

Step 1:

Action: Degrease, clean, and dust the cable surface where the sleeve will be applied.

✅ Use solvents that are compatible with the cable material.
✅ Clean 100 mm on both sides of the damaged section.

Step 2:

Action: Abrade the outer jacket of the cable using abrasive tape or sandpaper.

✅ Roughen 100 mm on each side of the damage for optimal adhesion.

Step 3: Remove the Adhesive Film

Action: Peel off the release liner from the adhesive-coated inner surface of the sleeve.

Step 4: Apply the Sleeve and Insert the Metal Channel

Action: Wrap the sleeve around the cable and slide the metal channel along the overlap to lock it.

✅ Extend the channel 10 mm beyond both ends of the sleeve.
✅ Confirm that the sleeve fits snugly around the cable.

Step 5: Start Heat Shrinking at the Center

Action: Begin applying heat at the centre of the sleeve and work outward.

✅ Apply uniform heat all around the sleeve.
✅ Focus extra heat along the metal channel.
✅ If necessary, bend the channel to follow the cable’s contours.

Step 6 Monitor Adhesive Flow

Action: Look for hot melt adhesive uniformly oozing from all edges.

✅ This indicates a secure and sealed installation.
✅ Let the sleeve cool fully before applying any mechanical stress.

Correct Installation of Hawke Cable Glands

Thorne & Derrick | Distributed from Stock | Approved Supplier | UK & Export Sales

Hawke Cable Glands Installation

Installing Hawke cable glands correctly is essential to ensure the integrity, safety, and performance and cable termination of your LV MV HV electrical systems—especially in hazardous environments like oil & gas, petrochemical and industrial sectors.

In this guide, we’ll walk you through the correct method for installing Hawke cable glands, share common mistakes to avoid, and explain why proper installation matters.

Step-by-Step: How to Install Hawke Cable Glands Correctly

1. Select the Right Cable Gland

Identify the cable type and choose the correct Hawke gland suited to both your cable and application. For example:

• 501/453/Universal – for unarmoured cable

• 501/453/RAC – for armoured cable

Confirm compatibility with:

• Cable diameter

• Armour type (SWA, braid, tape, etc.)

• Zone rating (Zone 1, Zone 2)

2. Prepare the Cable

• Strip the cable sheath as specified

• Ensure no damage to internal conductors or armour

• Trim and shape armour to fit cleanly inside the gland

3. Assemble the Hawke Cable Gland

Follow Hawke’s installation sequence precisely. Key components include:

• Entry item

• Inner and outer seals

• Armour cone and clamping ring (for armoured cables)

• Compression nut

Install in the correct order and apply any IP sealing washers where required.

4. Tighten & Secure

Use two spanners:

• One to hold the gland body

• One to tighten the compression nut to the recommended torque

This ensures:

• Proper grip on the cable

• Correct compression of sealing elements

• Safe electrical continuity and strain relief

The cable gland is permanently marked with various lines/numbers indicating the correct tightening level related to the cable diameter. Following the relevant cable gland Installation Instructions, the back seal should be tightened until a seal is formed on the cable outer sheath and then tightened one further turn

5. Final Cable Gland Checks

• Confirm ingress protection (IP rating)

• Check earth continuity for armoured installations

• Inspect for visible damage or loose components

Common Installation Mistakes to Avoid

• ❌ Using the wrong gland type for the cable

• ❌ Over-tightening or under-tightening

• ❌ Incorrect sequence of gland components

• ❌ Poor cable preparation or incorrect stripping of cable

• ❌ Forgetting to earth the armour

What Makes Hawke Glands Different?

Hawke’s range of cable glands are globally recognised for their robust construction, Ex-rated safety, and easy-to-install designs.

Whether it’s Ex d (flameproof), Ex e (increased safety), or Ex nR (restricted breathing), Hawke has a solution that safeguards your installation integrity—whatever the environment.

Need Support Choosing the Correct Cable Gland?

At Thorne & Derrick, we help you get it right the first time. As trusted Stockists & Distributors of Hawke cable glands, we provide:

• Technical support

• Product selection advice

• Same-day dispatch for stocked cable gland items

Contact our team today or explore our full range of Hawke cable glands.

Interface F Bushings & High Voltage Power Cable Connectors

Author | Rialdo Suwandi

Founder at Aldora Electric | Expert in Renewable Electrical Engineering & Cable Systems | Problem Solver | FIEAust CPEng NER

HV Bushings & Connectors

What Are Interface F Bushings?

How Do To Select the Right Cable Connector?

As medium voltage (MV) power systems grow in scale and capacity, manufacturers have introduced electrical equipment, such as transformers and switchgear, capable of handling up to 1250A at 52kV and 2500A at 36kV.

To ensure interoperability across manufacturers, these Interfaces are standardised under EN 50180 and EN 50181 as Interface F Bushings.

Furthermore, EN 50673 standardises 630A and 1250A bushings at 72.5kV.

What Are Interface F Bushings Used For?

Interface F bushings are typically used to connect gas-insulated switchgear (GIS) and transformers to cable circuits using separable connectors distributing electrical power at 11kV, 33kV and up to 66kV – manufactured by Nexans Euromold the connectors are suitable for cable termination of polymeric (XLPE EPR) insulated cables with copper wire or copper tape screen, wire armoured (SWA/AWA), wire braided or unarmoured cables into MV-HV Electrical Equipment with Interface F bushings.

Advantages of Electrical Equipment Bushings 

• Compact switchgear and transformer designs
• Interoperability across different manufacturers

Types of Interface F Bushings

As defined in EN 50180 and EN 50181:

F1 Bushings: Um ≤ 36 kV; Ir = 2500 A
F2 Bushings: Um ≤ 52 kV; Ir = 630 A
F3 Bushings: Um ≤ 52 kV; Ir = 1250 A

For 72.5kV high voltage power systems, EN 50673 defines the following:
F4 Bushings: Um = 72.5 kV; Ir = 630 A
F5 Bushings: Um = 72.5 kV; Ir = 1250 A

Note: F5 interfaces are commonly used in offshore wind applications but can adopted for large onshore installations as well.

Pictured | Nexans Q900AR-1Q900AR-2 Interface F Equipment Bushing 52kV MV HV

How to Select the Right High Voltage Separable Connector for Interface F Bushings

To ensure proper fit and reliable performance the following information must be established:

Interface type? e.g. F1
Maximum system voltage? e.g. Um = 36kV
Cable insulation type? e.g. XLPE
Conductor material and cross-section? e.g. copper, 800sqmm
Insulation over-diameter? e.g. 52.8mm
Number of circuits per phase? e.g. 2 circuits
Are surge arresters required? Confirm via an insulation coordination study

Interface F bushings enable safe, standardised, and high-capacity MV cable connections to GIS, and transformers, both for on-shore and off-shore applications.

Selecting the correct separable connector Interface F Connector —matched to interface type, voltage, current, cable type, and system design—ensures long-term reliability, safety, and maintainability.

Definitions of International Electrical Standards

EN 50180 | This European Standard is applicable to ceramic and resin insulated bushings having highest voltages above 1kV up to 52kV, rated currents from 250A up to 3150 A and frequencies from 15 Hz up to 60 Hz for insulating liquid filled transformers. This European Standard establishes essential dimensions, to ensure interchangeability of bushings and to ensure adequate mounting and interchangeability of mating plug-in separable connectors of equivalent ratings.

EN 50181 | This European Standard is applicable to insulated bushings for maximum voltages above 1kV up to 52kV, rated currents from 250A up to 2 500A and frequencies from 15 Hz up to 60 Hz for equipment other than liquid filled transformers. This European Standard establishes essential dimensions, to ensure adequate mounting and interchangeability of mating plug-in separable connectors of equivalent ratings.

EN 50673 | Extend the scope of the EN50180-1/2/3 and EN50181 for plug-in type bushings up to 72.5 kV

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 and Shrink Polymer Systems.