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Cable Link Boxes

Up to 9.0 kV SVL Protection
Ultra or Lite Models

Robust, IP68-Rated Stainless Steel Link Boxes for Underground HV Cable Earthing and Protection.

Insulect’s cable link boxes are designed to deliver robust sheath voltage protection and reliable performance in underground HV cable installations. Manufactured in Australia and tested to rigorous standards, our range includes models to suit direct earthing, SVL earthing, and cross-bonding applications. Built with IP68-rated stainless steel enclosures, these units withstand harsh environmental conditions, including below-ground and in-pit installations.

Each link box is tailored to network specifications and application needs, with options including 304 or 316 stainless steel, up to 9.0 kV SVL integration, and universal mounting for structure or pit. All models are engineered to minimise sheath current and safeguard critical underground cable assets through proven stress control, surge protection, and weatherproof reliability.

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Engineered for Safety, Connectivity & Network Efficiency

Applications include:
  • Direct Earthing or SVL Earthing through sheath voltage limiter surge arresters
  • Cross Bonding with insulation withstand between phases
  • Cable Sheath Protection using metal oxide sheath voltage limiters (SVLs)

Made for Demanding Environments

The Insulect range includes two models – Ultra and Lite – and numerous variants to support all underground cable configurations. Each design ensures a weatherproof connection point, whether for direct earthing or cross-bonding applications. Part of our broader Switchgear suite, Link Boxes integrate into substation, overhead, and underground cable applications.

Sheath Voltage Limiters (SVLs) and Earthing in Cable Link Boxes

Insulect’s cable link boxes are equipped to deliver safe and reliable sheath earthing solutions for underground high-voltage cables. Designed for direct earthing, SVL surge protection, and cross-bonding applications, they ensure effective discharge of transient voltages during faults, switching events, or maintenance procedures. Each unit is fully sealed to IP68, supporting use in indoor, outdoor, or in-pit installations.

Our SVL-compatible link boxes are engineered to integrate zinc oxide sheath voltage limiters rated from 1.5 kV to 9.0 kV, enabling high-energy absorption while protecting cable insulation. Options for 304 or 316 stainless steel bodies, various bonding cable diameters, and mounting types ensure broad compatibility. Whether in greenfield projects or retrofits, Insulect’s cable link solutions provide long-term reliability, operational safety, and peace of mind for utilities managing critical underground cable networks.

 

Key Specifications

  • Voltage Range: 1.5 kV to 9.0 kV (SVLs)
  • Short Circuit Withstand: Up to 63 kA for 1 second (Ultra); 40 kA for 1 second (Lite)
  • Enclosure Rating: IP68 for models.
  • Pressure Withstand: 250 kPa
  • Bonding Cable Compatibility: Single core (95-500 mm2) and concentric (95-300 mm2)
  • Link Conductors: Tin-plated copper, minimum 300 mm2
  • Mounting Options: Structure or in-pit configuration

What We Solve For

Cable link boxes must endure harsh conditions—moisture ingress, thermal expansion, mechanical stress, and corrosive environments—all while safeguarding vital underground cable assets. Insulect’s link boxes address these challenges with fully sealed IP68-rated stainless steel enclosures, robust internal connections, and high-performance sheath voltage limiters (SVLs) to suppress transient overvoltages.

With options for direct earthing, SVL protection, and cross bonding, our link boxes help reduce circulating sheath currents, extend cable life, and improve overall system reliability. Designed for ease of installation and long operational life, they support efficient network upgrades, minimise maintenance demands, and ensure dependable performance across utility and infrastructure applications.

TECHNICAL

Features & Functionality

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Comprehensive Configuration Options

Link boxes are available for direct earthing, SVL earthing, cross bonding, or combinations, supporting all underground cable protection practices.

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Built for Harsh Environments

All enclosures are stainless steel (316 or 304) and IP68 rated, ensuring corrosion resistance and ingress protection for in-ground or exposed installations.

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Above or Below Ground Mounting

Designed for flexible installation, Insulect link boxes can be installed in pits or on structures, accommodating diverse site requirements.

 

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Australian Designed and Tested

With over 20 years of local innovation, our link boxes are manufactured and tested in Australia to meet stringent utility standards.

Functionality & Options

  • Supports all major underground cable earthing practices: direct earthing, SVL earthing, cross bonding, or combined solutions.
  • Available in Ultra (316SS) and Lite (304SS) models to suit site durability and handling requirements.
  • Mounting flexibility: suited for structure or pit installation.
  • Enclosures tested to IP68 rating for ingress protection in harsh conditions.
  • Optional inclusion of SVLs (1.5 kV–9.0 kV) for sheath voltage protection.
  • Engineered and tested in Australia to meet local performance and compliance standards

Key Technical Specifications

  • Voltage range: 1.5 kV to 9.0 kV (SVLs)
  • Short-circuit withstand: Up to 63 kA for 1 second (Ultra), 40 kA for 1 second (Lite)
  • Enclosure rating: IP68 for all models.
  • Pressure withstand: 250 kPa
  • Bonding cable compatibility: Single core (95–500 mm²) and concentric (95–300 mm²)
  • Link conductors: Tin-plated copper, minimum 300 mm²
  • Mounting options: Structure or in-pit configuration
EXPERIENCE

Our Projects featuring Insulect Switchgear

Explore our project highlights to see where Insulect Switchgear is making an impact.
For tailored advice on whether this solution suits your network, please connect with our team here.

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Wunghnu Solar Farm
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Fortescue Aldoga, New 275kV Substation Switchgear

Where you'll find our Switchgear

You'll find Insulect-supplied and installed Switchgear across Australia and New Zealand -- our locally built Insulect range.

ADVANTAGES

Why Choose Insulect for Cable Link Boxes

Insulect’s cable link boxes are engineered and tested to perform in the most challenging underground environments. With over two decades of local design and manufacturing experience, our link boxes deliver reliable sheath voltage protection and earthing across a wide range of HV cable installations. Each unit is built from robust stainless steel, IP68-rated for ingress protection, and suited for either direct burial or above-ground use. Our designs integrate seamlessly into both new and retrofit projects, ensuring long-lasting, compliant performance.
 
Engineered for Local Conditions

From extreme temperatures and high-moisture zones to remote and high-contamination areas, our link boxes are purpose-built to meet the unique demands of Australian networks.

 

 
Flexible Configurations
We provide both ULTRA and LITE models, offering flexibility in weight, short-circuit withstand, and installation style.
End-to-End Support
Our local engineering team works closely with customers to provide tailored guidance, fast turnaround times, and lifecycle support from specification through to installation and beyond.
IMPLEMENTATION

Services & Support

Insulect offers comprehensive services and support for the products we manufacture and specialise in, enhancing value for local utilities, major energy users, equipment manufacturers, and service operators.

LOCAL TECHNICAL TEAM

Our local technical team provides exceptional support and expertise, ensuring quick response times and personalised service to tackle any challenges that may arise during project execution.


  
ENGINEERING DESIGN

Our team utilises advanced technology and industry knowledge to develop innovative and efficient high-voltage switchgear solutions, customised to fit the unique requirements of each project.


  
PROCUREMENT & LOGISTICS

We facilitate smooth procurement and logistics processes by sourcing from trusted, proven partners and coordinating timely deliveries, ensuring projects remain on schedule and within budget.

  
TESTING & COMMISSIONING Professional testing and commissioning support ensures that every high-voltage switchgear system functions safely and reliably, adhering to all regulatory standards and client expectations.  
TURNKEY PROJECT DELIVERY We are able to oversee every phase from concept to completion, providing comprehensive solutions that simplify complex projects and ensure successful outcomes.  
FACTORY VISITS
We facilitate client visits to our local manufacturing sites here in Australia, as well as overseas, for initial inspection as well as factory acceptance testing.
  
FROM THE BLOG

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