A Short Guide to Link Boxes

Link boxes are crucial to helping minimise the number of power supply interruptions to businesses and households. That’s because a link box provides flexibility to the underground low voltage electricity supply network by enabling circuits to be switched to route around problems.

A link box does what it says on the tin (or box) – it’s a box installed in a pit beneath the pavement which contains a low voltage cable joint with a removable link. It’s this link that allows the low voltage circuit to be switched.

Low Voltage Distribution

In towns and cities, low voltage distribution cables are connected through link boxes to form a network of LV cables leaving a local substation, usually as a series of a branched, open-ended radial cables. Under normal operation the links to adjacent substations in the network are removed. However, should a fault occur in the local substation, for example, these links can be replaced to enable the surrounding substations to feed power to the distribution cables that would have normally been supplied from the faulty substation.

Easy Isolation

Similarly, removing the links enables the length of cable between two link boxes to be easily isolated for repair, without the need to shut down the local LV network. It’s this feature that is crucial to keep busy networks running. The link box also has the facility to connect localised customers directly via a generator.

In the past almost all link boxes were manufactured from cast iron making them heavy and difficult to install.

New Lightweight Link Boxes

Now, following discussions with utility engineers, Prysmian has launched its revolutionary Bicon range of lightweight, easy to install, low voltage link boxes.

The boxes:

• Feature modular pit walls, making it easy to increase the depth of the link box simply by inserting an additional wall section.
• Can be jointed directly onto polymeric and paper insulated LV distribution cables, eliminating the need for intermediate lengths of polymeric cables and straight/transition joints.
• Can be jointed onto a live network possible because all live parts are shrouded.
• Use universal LV mechanical connectors (or can be designed to suit local jointing procedures).
• Have a reduced footprint making installation under congested pavements easier.
• Feature a strong, lightweight lid.

In addition, pre-fitted factory tailed units are also available to speed up direct replacement installations.

The new range features low voltage 2-way and 4-way underground tailed link disconnecting box and a 2-way and 4-way underground pre-cast link disconnecting box.

Prysmian’s new link boxes will revolutionise the way distribution network operators go about their business. Viva la revolution!