Conduit Fill
IET on-site guide factor method
Reading 4
m
Reading 5 m
Results
Fill
26%
OK
✓
Total cable factor120 (4 × 30)
Conduit capacity460 (20mm straight)
Headroom340
Suggested Materials
20mm PVC conduit (3m length)
2 pc
20mm conduit coupling
1 pc
20mm conduit saddle
500mm centres
10 pc
20mm 90° bend / inspection elbow
2 pc
Estimates use standard UK trade rules of thumb. Always check the bag/spec on the day.