How to Choose PVC Trunking Size
Start with the cables and route, then choose the trunking profile. A width and height on a product drawing describe the profile; they do not automatically tell you how many cables it can carry.
1. Make a cable schedule
List each cable type, quantity and actual outside diameter, including insulation. Record power, data and control circuits separately. Two cables with the same conductor size can have different overall diameters.
2. Check usable space
Ask for the internal cross-section of the selected profile and each compartment. Wall thickness, partitions, mounting features and outlet boxes reduce available space. Use the applicable installation rules and the manufacturer’s capacity information, rather than treating the external width multiplied by height as the usable area.
For an initial geometry estimate, the area of a round cable is π × diameter² / 4. Ten cables with a 6 mm outside diameter occupy approximately 283 mm² before allowance for packing, bends and the applicable fill limit. This is a worked example, not a capacity rating for a Budgie profile.
3. Allow for the whole route
Check the narrowest fittings, internal and external corners, tees and outlet positions. A larger straight section cannot compensate for a tight corner that violates the cable’s minimum bend radius. Plan space for agreed future additions and confirm that the lid closes without compressing cables.
4. Select the right family
- Mini trunking: consider for compact surface routes after checking capacity.
- Medium and maxi trunking: compare when the cable schedule needs more space.
- Dado trunking: compare when the route also needs outlets and separate compartments.
Send a useful enquiry
Include a cable schedule, route drawing, preferred dimensions, length, colour, mounting surface, fittings and destination country. Ask for confirmation of internal dimensions, compatible accessories and the exact product documentation.
There is no single fill percentage suitable for every trunking installation. Panduit’s published wiring-duct table illustrates a product-specific capacity method; do not transfer that table to another product or jurisdiction.
Technical reference: Panduit wiring-duct capacity method.
Continue your selection
Make your requirements clear
Send your product type, dimensions, quantities and destination market. Our team can help confirm the specification before quoting.
Get a Quote