Port Blair, Apr 22: The Electricity department has advised all concerned to exercise utmost caution and to obtain clearance of the concerned Junior Engineer while undertaking excavation/digging works of the earth on either side of the road where underground high tension power cables are also laid so as to avoid causing damage to such cables and to safeguard from the serious threat of electrocution. Necessary markings have been made in the routes where underground power cables have been laid so as to make the people aware of it, the Executive Engineer (HQ), said in a press communication.