Crafting a better housing for underground cable earthing.

A cable earthing connection box (Link Box) is a critical part of high-voltage underground cable systems. The application has some unique challenges, both in terms of physical and electrical requirements.

Firstly, a Link Box provides a sealed, weatherproof enclosure for bonding cable earths at what is the weakest point in the system – cable joints and terminations.

Secondly, it provides an easy access point for maintenance purposes, to allow testing of shield breaks and cable connections.

Link Boxes may be configured as single point bonding for the cable earths, or may be cross bonded to reduce or eliminate circulating currents.

SVL (Sheath Voltage Limiters) are normally provided in Link Boxes to ensure that transient over voltages, due to lightning or switching surges, don’t cause any breakdown of the cable jacket or other parts of the cable system.

A link box must allow for bonding of the cable earths, protect the cable system and facilitate safe access for maintenance crews.

The Insulect solution to this problem is to design, manufacture and individually test each Link Box right here in Australia to ensure the highest quality standards.

We get to know each customer’s individual needs and develop a custom solution from one of our many base models. The result is a Link Box that is simple to install, safe to maintain, and most importantly, that performs reliably underground, year after year, in all conditions.

Not only are Insulect Link Boxes made locally, but so are most of the components, including the sheath voltage limiters (SVLs), which are also produced in the Sydney plant.

The results of this custom manufacturing approach speak for themselves – over two decades of successful operation in many countries with more than two dozen utility customers.

This partner content is brought to you by Insulect. For more information, visit

Lauren brings a fresh approach to content. While she’s previously written for publications as diverse as Australian Geographic, The Border Watch and Girlfriend, she’s found her true passion in her current role as an editor in the world of energy and infrastructure trade magazines.

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