Protective or installation trunking systems are among the most widely used solutions for the organisation, routing, and protection of cabling in electrical, telecommunications and automation installations. Commonly referred to as cable trunking or simply trunking in everyday installer jargon, they provide a safe, accessible and highly adaptable means of installation. This makes them particularly suitable both for retrofit environments—where structural work is impractical—and for new-build applications.
Despite being a well-established solution, their application still raises a number of questions: what types are available, how to select the right one, and which standards must be met. In this article, we address some of the most frequently asked questions on the topic, adopting an informative approach aimed at those entering the sector.
Let’s start with the basics. A trunking system is a profiled enclosure designed to protect, route, and organise electrical conductors and other electrical components, and is enclosed by a removable lid.
Its primary function is to ensure a safe, tidy, and accessible installation, preventing damage to the conductors and facilitating future extensions, modifications, or maintenance work.
Sometimes the terms trunking, mini trunking, or covered cable trays are used interchangeably, which can cause some confusion. However, from a technical point of view, they are not the same. For a system to be classified as protective trunking, simply adding a cover is not enough. It must comply with the BS EN 50085 standard and provide a defined IP protection rating, such as our cable tray 66.
Depending on their application within the installation, there are different types of trunking systems. The most common include:
Distribution trunking is intended for routing and protecting cabling along walls or ceilings in electrical and communication installations, such as our Trunking 73.
It is typically surface-mounted and features an external cover.
This allows quick and easy access to the cables and wiring for maintenance or future extensions. In addition, internal compartmentalisation enables clear separation of circuits.
Trunking for accessory integration is designed to accommodate sockets, data outlets, or other wiring devices directly within the trunking profile, for example our Trunking 93.
This type of trunking combines cable routing with the installation of wiring accessories along the run.
Skirting or floor trunking is used to distribute cables and wiring around room perimeters or at floor level, for instance our Skirting board ducts 80 or our Floor trunking 74.
They are particularly suitable where cables and wiring need to be routed close to workstations or across circulation areas.
Mini trunking, of compact dimensions, is employed for surface-mounted installations with a limited number of cables, such as our Mini trunking 78.
Their small profile allows for a discreet installation on walls or ceilings.
In practice, the selection depends on the type of project, the number of cables, and the specific technical requirements of each installation.
Protective trunking systems are mainly manufactured from plastic materials. The most common is PVC, although trunking made from halogen-free compounds is also available.
At Unex, we offer both types of raw materials: U23X for PVC, and U48X or U43X for halogen-free solutions. These are our own proprietary formulations, developed to ensure optimal performance in demanding environments.
Furthermore, U48X and U43X contain a 100% recycled thermoplastic component, providing added value from a material sustainability perspective.
Protective trunking systems offer several key benefits:
For these reasons, they are particularly well suited for refurbishment projects, office environments, industrial facilities, and any setting where cabling needs to evolve in line with changing operational requirements.
Correct sizing of trunking is a key factor in ensuring a safe and efficient installation.
Several factors must be considered, including the number of cables, their cross-section, the type of insulation, and the potential for future extensions. Undersized trunking can hinder both installation and maintenance. By contrast, appropriate sizing allows for proper cable organisation and ensures the installation remains accessible.
Trunking systems are not limited to electrical wiring. They are also widely used to route different types of services within the same installation. The most common include:
When different services share the same trunking, effective circuit segregation becomes essential. This reduces the risk of interference and simplifies maintenance tasks. Segregation is achieved by means of internal partitions or compartments, allowing each service to be clearly organised within the system. In all cases, the relevant regulations for each type of installation must be taken into account.
Yes — as long as you choose systems specifically designed for that purpose.
In outdoor applications, it is important to ensure that the system is UV‑resistant, withstands temperature variations, offers high impact resistance, and is installed strictly according to the manufacturer’s instructions.
For this type of installation, Unex provides solutions such as the Trunking 73 or the Cable tray 66 with cover, both designed to keep cabling protected even in demanding environments.
Protective trunking systems must comply with the standards applicable in each country and sector.
In Europe, the UNE-EN 50085 standard defines the requirements that cable trunking and cable ducting systems must meet, including tests for mechanical strength, fire performance, thermal stability, and impact resistance.
Installing trunking systems is straightforward and versatile. They can be fixed using:
A reliable fixing method is essential to ensure the stability and durability of the installation. At Unex, all our trunking systems are supplied with pre‑drilled base perforations, allowing easy fixing to walls using screws and wall plugs. Some ranges also include an adhesive backing, avoiding the need for drilling and further simplifying installation.
Unex trunking systems include a wide range of accessories to accommodate any routing configuration and the integration of components: internal, external, and flat angles; end covers, joint cover pieces, and junctions; adaptors for wiring accessories or gas outlets, among others.
Beyond improving the overall finish of the installation, our accessories also help to meet specific technical requirements, such as achieving an IP4X degree of protection.
At Unex, we have over 60 years of experience in developing innovative insulating systems for cable management in electrical, telecommunications, and HVAC installations. This expertise has enabled us to support the evolution of the sector, from the first cable routing systems in bluildings to today’s increasingly demanding and complex infrastructures.
Understanding what trunking is, the different types available, and the applicable standards is the first step towards designing installations that are well organised, accessible and prepared for future expansion.
If you have any questions about selecting the appropriate trunking system, sizing it correctly, or identifying the most suitable solution for your installation, our technical team will be pleased to assist.
You can contact us by emailing australia@unex.net.
We will be delighted to support you.
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