Cable trunking and cable trays solve different cable-management problems. Trunking provides an enclosed pathway that can support segregation and physical protection, while trays provide open or ventilated support with easier access and generally better heat dissipation.
Ruwais Steel manufactures cable trunking and cable trays for UAE commercial, industrial and infrastructure projects. Selection should follow cable type, environment, access, thermal conditions and the approved electrical design.
Cable Trunking vs Cable Tray: Quick Comparison
| Factor | Cable Trunking | Cable Tray |
|---|---|---|
| Containment | Enclosed with cover | Open / perforated |
| Ventilation | Lower | Higher |
| Physical protection | Higher | Moderate unless covered |
| Visibility | Low when closed | High |
| Segregation | Can use compartments | Dividers or separate trays |
| Maintenance | Cover removal required | Direct access |
What Is Cable Trunking?
Cable trunking is an enclosed containment system with a base/channel and cover, plus fittings for bends, branches and transitions.
IEC 61084-1:2017+A1:2024 specifies general requirements and tests for cable trunking and ducting systems within its scope. Ruwais Steel's range includes bends, tees, weatherproof configurations, service-outlet trunking and raised-roof arrangements.
What Is a Cable Tray?
A cable tray is an open support system, often made from perforated formed steel. IEC 61537:2023 addresses cable tray and ladder systems.
For heavier power routes, cable ladders may also be considered where greater ventilation and support for larger cables are required.
1. Enclosure and Protection
Trunking can reduce casual contact and exposure to debris. A cover does not automatically make a system weatherproof or dust-tight. Environmental performance depends on joints, gaskets, penetrations and the actual system design.
Tray systems remain open for access and ventilation. Covers can be added, but designers should then review thermal effects, fixing and outdoor wind exposure.
2. Cable Fill and Future Capacity
Do not size trunking simply by fitting cable circles into a section drawing. Fill, grouping, installation method, bend space and thermal effects must comply with the electrical design.
For trays, width must also be checked against cable arrangement and structural load. Physical spare space does not guarantee structural spare capacity.
See the cable tray load capacity guide for more detail on load, support spacing and deflection.
3. Ventilation and Cable Temperature
Open trays dissipate heat more freely than enclosed trunking. Changing the containment method can affect cable current-carrying conditions, particularly in high ambient temperatures or dense cable groups.
The electrical engineer should review derating rather than treating containment as a neutral substitution.
4. Power, Data and Control Segregation
Projects may require separation between power, data, ELV, fire alarm and control circuits.
Trunking can use internal compartments where the system is designed for it, while trays can use dividers or separate routes. Required separation must follow applicable standards and the approved project design.
5. Fittings and Bend Radius
- 90° and 45° bends.
- Internal and external risers.
- Tees and crosses.
- Reducers.
- End caps.
- Couplers.
- Dividers.
The largest cable on the route can govern the required fitting radius. Tight elbows can make pulling difficult and can exceed cable bending limits.
6. Maintenance and Future Changes
Open trays provide fast visual inspection and easy cable additions. Trunking provides a cleaner enclosure but requires cover removal.
Facilities with frequent moves and changes should consider lifecycle access, not only first-installation appearance.
7. Corrosion Protection
Pre-galvanized steel, HDG after fabrication, stainless steel and specified coating systems can suit different environments.
Read the Ruwais Steel corrosion selection guide before using “GI” as a generic finish description.
8. Weatherproof Trunking Requires Defined Performance
Weather-resistant trunking should consider flange geometry, gasket continuity, cover fixing, joints, penetrations and drainage.
Ruwais Steel's current range includes weatherproof configurations with outward flanges and gasketed arrangements. The final product must match the project's specified environmental performance.
9. Earthing and Bonding
Metal containment may require bonding and continuity provisions. Coatings, joints and corrosion can affect electrical contact.
Mechanical assembly should not automatically be assumed to provide protective continuity unless the complete system is designed and approved for that purpose.
10. MEP Coordination and Access
Trunking needs sufficient space to remove covers. Tray needs enough space to lay, secure and maintain cables.
Both systems require access at bends, tees and supports. BIM coordination should include installation and maintenance zones, not only nominal containment dimensions.
Which System Fits Which Application?
| Application | Starting Option | Reason |
|---|---|---|
| Commercial distribution | Trunking / tray | Enclosure, appearance and cable type |
| Heavy industrial power | Tray / ladder | Load and ventilation |
| Data / telecom | Wire mesh / tray | Accessibility |
| Segregated indoor circuits | Compartment trunking / separate routes | Organised separation |
| Outdoor route | Project-specific system | Exposure and corrosion govern |
Cable Trunking RFQ Checklist
- Width and depth.
- Base-metal thickness.
- Material and finish.
- Cover fixing method.
- Compartments and dividers.
- Fittings and bend radii.
- Environmental requirement.
- Couplers and accessories.
- Bonding provisions.
- Required certificates and documentation.
Common Cable Trunking and Cable Tray Selection Mistakes
- Using trunking and tray as interchangeable terms: they provide different levels of enclosure, ventilation and accessibility.
- Ignoring thermal derating in enclosed containment: cable operating conditions can change when ventilation is reduced.
- Overfilling trunking: physical space alone does not confirm a compliant cable arrangement.
- Ordering straight lengths without fittings: bends, tees, reducers and accessories should be included during procurement.
- Calling ordinary covered trunking weatherproof: environmental performance depends on the complete system design.
- Ignoring cover-access space: sufficient maintenance clearance should be coordinated during design.
Specify Cable Containment Around the Electrical Requirement
Ruwais Steel supplies cable trunking, cable trays, cable ladders and wire mesh trays for UAE commercial, industrial and infrastructure requirements.
Send your BOQ, sizes, material finish, fittings and segregation requirements for project review.
Frequently Asked Questions About Cable Trunking and Cable Trays
Is cable trunking better than cable tray?
Neither is universally better. Trunking provides enclosure, while tray provides ventilation and direct access. Selection depends on the electrical and environmental requirement.
Can power and data share trunking?
Only where applicable rules and the project design permit it with the required separation or protective segregation.
Which standard applies to cable trunking?
IEC 61084 is a current international series for cable trunking and ducting. The approved project specification should govern.
Technical References
- IEC 61084-1:2017+A1:2024 — Cable trunking and ducting systems.
- IEC 61537:2023 — Cable tray and cable ladder systems.
Engineering note: cable fill, thermal derating, segregation and bonding must be verified by the responsible electrical designer.
