Selecting the right cables for tunnels and overhead transport systems

Jul 29, 2023

Australia has seen a dramatic increase in imports in recent years, up 34 per cent from 2020 to 2022. This significant rise has created an increased demand for infrastructure to facilitate the import, storage and distribution of these goods. As Australian capital cities continue to become increasingly dense, building and cabling tunnels and overhead transport systems demands additional requirements that aren’t present in traditional surface transport systems.

For example, tunnel cabling needs to not only be flame retardant but, depending on the application, may also need to continue to operate under fire conditions, often referred to as a circuit integrity cable.

There are a number of standards that specify the performance these cables need to meet under fire conditions including IEC 60332 and Australia’s own AS/NZS 3013. Fire within a tunnel can also result in loss of life due to toxic and corrosive gases released when plastics burn, so the use of Low Smoke Zero Halogen (LSZH /LSOH) materials is preferred or often mandated for these installations.

Again there are a number of national and international standards that govern these characteristics such as IEC 60754-1 and IEC 60754-2 that assess the amount of halogen gas released using various methods, and IEC 61034-2 that grades the level of smoke generated when burned.

To help manage all these various requirements, there are other standards that combine all the various characteristics into a single rating, hoping to aid and simplify the selection of cables. Typical of these standards is AS/NZS 4507 that uses its own classification system to combine the various requirements into a single rating and using this approach can help simplify requirements.

Some cable types do not easily fall into these standards. For example, AS/NZS 3013 cannot be applied to optical fibre cables although this is often requested by designers or legislators. Navigating these various demands can be confusing and difficult. The situation is further complicated by the sheer range and variety of cables required for modern control and monitoring systems.

Supplying cables to australia’s biggest projects

Most of these systems are custom designed for the application, so standard ‘off the shelf’ cables are not normally available and require custom cable designs to be offered. These designs go through several iterations as the circuits are tuned for optimal performance, ease of installation and cost. All these factors put a huge demand on the cable supply and this can get exponentially more difficult as the number of cable suppliers increases.

Madison Express understands these issues and has focused on building its portfolio and expertise in this area to provide a number of solutions for cabling infrastructure. By focusing on security, communication, control, and transport cables, Madison is able to offer solutions for several of the cable supply packages often associated with these major projects.

With both its own Garland brand and a number of reputable international brands including LEONI and R&M, Madison has already supplied several projects including the Sydney Metro Northwest Project, WestConnex M4-M5 Rozelle Interchange Tunnel, the Western Roads Upgrade in Victoria and Grafton Prison.

For more information on how Madison Express can be the local expert for your next cabling infrastructure project, please visit madisonexpress.com.au.