using separate protective tubing in the conduits or ducts

Full Title

Installations of electric cables or lines or protective tubing therefor in or on buildings, equivalent structures or vehicles (installations of bus-bars H02G5/00; overhead installations H02G7/00; installations in or on the ground H02G9/00) > Installations of cables or lines in walls, floors or ceilings > the cables or lines being installed in preestablished conduits or ducts > using separate protective tubing in the conduits or ducts