Galvanised Steel Trunking
Galvanised steel trunking is a rectangular metal cable enclosure with a removable lid, used to carry and protect large numbers of cables in commercial and industrial buildings. We stock Marshall-Tufflex metal trunking in 50 x 50mm, 75 x 75mm, 100 x 100mm and 150 x 150mm, supplied in 3m lengths.
The range also includes matching end caps, gusset bends and tees with inside, outside and top lids, plus Unistrut flat and adjustable bends. Trade account holders get trade pricing; order in-stock lines before 5pm Monday to Friday for next working day delivery to NI and ROI.
How to choose galvanised steel trunking
Steel trunking provides strong mechanical protection, good fire performance and the capacity to add cables over the life of a building. It is common in factories, warehouses, plant rooms, schools and retail units.
Choosing a size
Size trunking by the number and size of cables it will hold, plus room for future additions. Published guidance uses cable and trunking factors and a space factor (commonly 45%) to check capacity, which also helps prevent overheating. As a rough guide:
- 50 x 50mm – smaller distribution runs and final circuits.
- 75 x 75mm – medium runs and mixed circuits.
- 100 x 100mm – main distribution routes.
- 150 x 150mm – large backbone routes and submain distribution.
Fittings to plan for
Gusset bends and tees change direction while keeping a smooth internal radius. Choose inside lid, outside lid or top lid fittings according to which face of the trunking the lid is on. End caps finish each run, and couplers join lengths together.
Earthing and installation
Steel trunking can form part of the protective earthing arrangement, but only if electrical continuity is maintained across every joint. Fit earth continuity straps or links at joints and fittings as the manufacturer recommends, and test continuity after installation. Deburr every cut edge, fit grommet strip or bushes where cables pass through, and support the trunking at regular intervals using suitable strut and accessories. Where segregation is needed, use a compartmented system or separate runs.
For entries into boards or boxes, use grommet strip to protect cable sheaths, and for very heavy cables consider cable tray and basket instead.
Meteor Electrical stocks metal trunking and fittings at our 200,000 sq ft Cookstown warehouse. Free delivery applies over £30 / €35 ex VAT, or collect from our trade counter.
FAQ's
- Can galvanised steel trunking be used as an earth?
- How many cables can fit in steel trunking?
- How do I cut galvanised steel trunking?
- When should I use steel trunking instead of PVC trunking?
- What is the difference between inside, outside and top lid bends?
- Can I order metal trunking with next day delivery?