Selecting a Cable Enclosure
A cable enclosure is designed to protect its contents (cables, connectors, equipment etc.) against external influences. The structure also acts as a shield to prevent its potentially live contents from causing damage or injury to passersby.
Cable pits are positioned on cable routes to provide branching or bending points and to allow access for jointing and maintenance. Common cables routed through cable pits include data/communication fibre-optic cables and low voltage electrical wiring (higher voltage cables typically go overhead or extremely deep underground).
In contrast, surface cable ducting systems become the cable route and allow low voltage cables and other utilities to be laid directly along a trafficable pavement. They can be continually accessed through removable covers. The structure enclosing the services is typically continuous.
Codes Governing Use of Cable Enclosures
There are various codes governing the use of cable enclosures relevant to both the electrical and communications industries. Dependent on the application, it is ACO’s recommendation that all designers and installers reference these documents or seek further advice from relevant legislative authorities and consulting engineers.
Electrical
For electrical installations, certain cable types are drawn into pits. AS/NZS 3000 chiefly defines these cables as Category A underground wiring systems and dependent on the cable type, they are housed in a cable route (between pits) inside light flexible to heavy duty orange conduits.
Communications
In the communications industry, cables (typically to transmit video, data and/or voice) are generally housed in white conduits and are drawn along cable routes into cable pits. These routes are specifically termed pathways in a cable management system. Enclosures in the communications industry are also known as spaces or handholes and are all classified as cabling products governed by the requirements set out in AS/ACIF S008 for the customer side of the boundary. AS/NZS 3084 reviews the typical pit sizes for communications installations. Additionally, many telecommunications carriers also have their own specific criteria and these are generally documented.