Guide to UK Cable Tray Sizes

Cable Tray Overview

A cable tray is a type of cable management system. There are different types and configurations of cable trays to facilitate a straightforward installation. Cable trays are available in open, perforated and solid-bottom designs to accommodate different types and installation requirements. These various styles, sizes and designs cater to different environments. The right cable tray can improve the overall safety and longevity of the installation.

What is the Role of Cable Trays in Electrical Installation? 

Nearly every commercial and industrial building requires cable management for electrical installations. Cable trays help store and guide cables in a sturdy and secure solution that prevents them from sagging, tangling and overcrowding. They provide even weight distribution and increased support for safe installations while minimising electromagnetic interference.

Application of Cable Trays

Some applications of cable trays include supporting heavy power distribution cables in industrial facilities, above drop ceilings in offices and supporting cable routing in high-moisture environments. Essentially, any building that requires safe, contained and accessible wiring will require some form of cable trays.

Understanding Cable Tray Sizing

Choosing the right cable tray for your installation requires knowing the type of cables (power, data or both) that are being routed, the number of cables, along with any weight constraints. This information simplifies the ordering process, focusing on the required width, depth, length and capacity for the installation.

Standard Cable Tray Widths

Standard cable trays are available in a variety of widths, from 50mm to 900mm. This is beneficial for different installation needs and settings. 

The 50mm to 150mm range is excellent for smaller cable runs, data cabling, telecommunications systems and light-duty electrical installations where cable volumes are relatively low. The 200mm to 400mm range is commonly used for medium-sized power and data cable installations in commercial buildings and industrial facilities. The 500mm to 900mm range is ideal for high-capacity cable runs, heavy power distribution systems and large-scale industrial installations.

Cable tray width sizes:

• 50mm
• 75mm 
• 150mm 
• 225mm
• 300mm
• 450mm
• 600mm
• 750mm
• 900mm

Standard Cable Tray Depths

Equally important are cable tray depths, as these dictate the quantity of cables a system can support.

The 12mm to 18mm range is ideal for lightweight use, such as guiding data cables in commercial offices. 25mm cable trays are better for general commercial and retail installations for smaller power cables. For heavy-duty applications, the 50mm to 75mm range supports cable routing for warehouses, plant rooms and multi-cable routing. 

Industrial applications, such as supporting high-voltage power, heavy armoured or oil/gas applications, require cable trays in the 100mm to 150mm depth range. 

Cable tray depth sizes include:

• 15mm
• 25mm
• 50mm
• 100mm

Standard Cable Tray Lengths

The length of a cable tray is designed in straight sections to accommodate different installations. Standard tray lengths make it easier to create continuous cable routes across large areas while reducing the number of joints required. Longer sections can help speed up installation, while shorter lengths may be more suitable for confined spaces or complex routing requirements.

Cable tray length sizes include: 

• 2.5m
• 3.0m

Metric vs Imperial Sizing for Cable Trays

Cable tray sizes may be specified using either metric or imperial measurements. Metric sizing is the most common standard in the UK. In metric, dimensions are provided in millimetres (mm). In imperial sizing, inches are used to provide dimensions. When selecting or replacing cable trays, it is important to ensure measurements are converted correctly.

How to Choose the Right Cable Tray Size

The right cable tray size will depend on the purpose, location and environment. These specifications will determine what needs to be prioritised. Larger power cables and high cable volumes will typically require wider and deeper trays to maintain safe spacing.

Smaller cables, such as data, telecommunications and light-duty electrical cables, can often be accommodated within narrower and shallower tray systems. It is also worth considering future expansion requirements to ensure the cable tray can support additional cabling if the installation grows over time.

Key Considerations for Choosing Cable Tray Sizes

Cable Weight and Loading

The amount of weight a cable tray will have to support will influence the size, as heavier cable loads often require wider and deeper trays. This helps distribute weight evenly, prevents sagging and ensures the installation remains structurally secure.

Cable Type

Different cables require different types of support. Larger power cables, fibre optic cables and data cables each have unique spacing and handling requirements, which can affect the width, depth and overall design of the cable tray selected.

Cable Diameter

The overall cable diameter determines how many cables can fit, dictating the required cable tray size. Larger diameter cables take up more space and may require wider trays to maintain safe spacing..

Cable Segregation Requirements

Certain types of cable require segregation to prevent electromagnetic interference as well as an accumulation of heat. The size of the cable tray may need to increase to accommodate separate cable runs while maintaining compliance and safe operating conditions.

Ventilation

If ventilation is important, then perforated cable trays can prevent overheating. By understanding the intended use, it’s easier to select a cable tray that will perform as intended. Adequate airflow may require additional tray width or spacing to support cooling and prevent heat build-up.

Expansion

When accessibility is essential, you may want a more open design that enables simpler maintenance. It is also worth considering future expansion, as selecting a slightly larger tray can provide additional capacity for new cables without requiring significant modifications.

Cable Trays at Lenson Select

Lenson Select supplies high-quality Cable Trays in a wide range of sizes to suit commercial and industrial installations across the UK. Custom cutting is available upon request, reducing on-site preparation and installation time. Trade account holders can also benefit from exclusive pricing, priority service and a range of account advantages. Contact Lenson Select today to discuss your requirements or request a quotation. Fill in our contact form, give us a call on 0121 553 6699 or email us at sales@lenson-select.co.uk.