Cable trays carry power and data cables through buildings, plants and service shafts. The right tray keeps cables cool, supported and easy to add to later. This guide covers the main tray types, finishes, sizing and the accessories you should not forget when ordering.

Types of cable tray

Perforated tray

A solid sheet-metal channel with punched holes along the base. The holes let heat escape and give many points to tie cables. Perforated trays are the most common choice for small and medium power cables, control cables and mixed runs in commercial buildings and factories.

Ladder tray

Two side rails joined by rungs, like a ladder. It gives excellent ventilation and is strong over longer spans, so it is used for heavy power cables and long horizontal runs such as in plant rooms, substations and industrial sheds.

Raceway or trunking (covered tray)

A closed tray with a cover. It protects cables from dust, water dripping from above, falling objects and tampering, and looks tidy where cables are visible. Ventilation is lower, so cable sizing must allow for it.

Wire mesh tray

Light welded wire baskets, popular for data, CCTV and low-voltage cables above false ceilings and in server rooms. Easy to cut and bend on site.

Choosing the material and finish

Sizing the tray

1. List the cables that will run in the tray, with their outer diameters.
2. Add up the cable widths if laid in a single layer, or the total cross-section area if bunched.
3. Leave room. Do not fill a tray to the brim. Keeping it roughly half full helps cables run cooler and leaves space for future circuits. Your electrical designer may specify an exact fill limit and derating.
4. Pick a standard width and depth. Common widths are 100, 150, 200, 300, 450 and 600 mm, with side heights such as 25, 50 and 75 mm.
5. Check the sheet thickness and support spacing against the manufacturer's load table. Heavier cable loads need thicker sheet or closer supports.

Supporting the tray

• From concrete ceilings, trays are usually hung on threaded rods with drop-in anchors, with a slotted channel or angle as a cross-support (a trapeze).
• On walls, use wall brackets or cantilever arms fixed with suitable anchors.
• From steel beams, use beam clamps so you do not need to drill or weld the structure.
• Add a support close to every bend, tee and joint, as these are the weak points.

See our step-by-step guide to hanging MEP services with threaded rods and channels.

Accessories checklist

• Bends (90° and 45°), tees, crosses and reducers.
• Couplers or joint plates with nuts and bolts.
• Covers for exposed or vertical runs.
• Earthing continuity links across each joint, and the tray system bonded to earth as per your electrical design.
• Cable ties or clamps, and edge protection where cables leave the tray.

This guide is general information for buyers. Always follow the anchor or fixing manufacturer's data sheet and your project engineer's design for load-bearing and safety-critical work.