Excavation width
This depends mainly on the outside diameter of the duct used for the cable as well as on the necessary space for:
- installing the ducts: 4 cm is allowed between the ducts for filling with concrete
- lacing:
an extra width of 4 cm on either side of the trench must be allowed for installing the lacing.
There should be 10 cm between the lacing and the ducts to be filled with concrete.
- space between two lines: This distance depends on the thermal assumptions used for calculating the transmission capacity of each power line. In practice, a minimum distance of 70 cm is recommended.