H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
H02G3/00—Installations of electric cables or lines or protective tubing therefor in or on buildings, equivalent structures or vehicles
H02G3/28—Installations of cables, lines, or separate protective tubing therefor in conduits or ducts pre-established in walls, ceilings or floors
H02G3/281—Installations of cables, lines, or separate protective tubing therefor in conduits or ducts pre-established in walls, ceilings or floors in ceilings