Administrations and private operating agencies should have available safety instructions for guidance of staff if it is necessary to work on telecommunication lines in which dangerous voltages may occur. Such guidelines should take into account any national regulations or other requirements. Where it is desired to supplement existing guidelines or regulations, the following precautions should be considered in the drafting of safety instructions. It is not intended that all of the safety precautions listed in §§ 6.2 and 6.3 should be observed in every case. They should be selected and applied as appropriate to the work operations being performed, the type of line involved and the type of protective measures applied to the line.