PRECAUTIONS TO BE TAKEN DURING WORK 2.4.7 PREVENTING ELECTROCUTION q Digging operations near overhead electric lines are extremely dangerous and they may also cause death due to electrocution; for this reason, when working near overhead electrical lines, always respect the minimum safety distances prescribed by the competent authorities and by the accident-prevention rules in force. q As far as underground long-distance lines are concerned, the minimum distance depends on the covering of the ducts in which the cables are laid. q The basic safety precautions to be taken to prevent this risk are the following: 1 - Wear shoes with thick rubber or leather soles.
2 - Request the aid of another person who can warn you if the machine gets too close to the electric line. 3 - Operate at low speed. 4 - Get acquainted with the behaviour rules to be followed in case of electrocution. 5 - Keep the phone number of the electric energy company and of the nearest hospital at hand. q If the work equipment gets accidentally entangled in the cables, the operator must not leave the cab until the electricity company has insulated the line. q When carrying out this kind of operations, warn everyone standing in the work area to maintain a safety distance from the machine and the work equipment.
q Ask the electricity company in advance what are the voltage of the cables and the minimum safety distance. q The minimum distances from overhead lines can vary in the different countries, according to the climate and to the humidity percentage in the air. Indicatively, the distances indicated in the table should be respected. 46 DANGER Cable voltage Min. safety distance 1.0 kV (distribution line) 5 m 6.6 kV (2–3 insulators) 5,2 m 33 kV (min. 3 insulators) 5,5 m 66 kV (min. 6 insulators) 6 m 154 kV (min. 10 insulators) 8 m 275 kV (min. 19 insulators) 10 m