The present disclosure relates to a method for festooning a power cable while deploying it in a deployment site comprising a rail having a start and an end, the method comprising the steps of: providing the cable with a plurality of cable holders slidably movable along the rail, each two consecutive holders being spaced at a holder predetermined distance on the cable; providing a festooning apparatus after the start of the rail, the festooning apparatus comprising a lowering device movable between a raised position and a lowered position; deploying the cable along the rail by repeating the following sub-steps: engaging on the rail one holder after the other and moving them thereon; when one holder oversteps the festooning apparatus, operating the festooning apparatus to move the lowering device from the raised position towards the lowered position, thus engaging the cable at a point between two consecutive holders; when the lowering device reaches the lowered position, obtaining a sagged portion of cable and a shortening of the holder predetermined distance; operating the festooning apparatus to move the lowering device from the lowered position towards the raised position, thus disengaging it from the cable; fixing the shortened holder predetermined distance between two consecutive holders at each side of the sagged cable portion; and advancing the sagged cable portion along the rail.