This Recommendation deals with the risk management of lightning protection of telecommunication networks using cables with metallic conductors. The risk assessment is limited to physical damage and failure of insulation of telecommunication lines (buried or aerial cables, shielded or unshielded cables) which can cause the loss of service. This Recommendation provides a procedure for the evaluation of such a risk. Once an upper tolerable limit for the risk has been selected, this procedure allows the selection of appropriate protection measures to be adopted to reduce the risk to a level at or below the tolerable limit. This Recommendation shall be used together with [ITU-T K.47], which provides the risk assessment and the protection measures against lightning flashes to the telecommunication line and to connected structures, and [ITU-T K.46], which provides the risk assessment and the protection measures against lightning flashes near the telecommunication line. The protection need for line equipment (such as multiplexers, power amplifiers, optical network units) and line termination equipment is not considered in this Recommendation and it should be evaluated using the risk assessment applied to the structure where the equipment is located (i.e., exchange, customer's building, or remote electronic site). The protection of persons using telecommunication equipment inside the customer's structure, from dangerous situations caused by touch voltages is outside the scope of this Recommendation and it should be evaluated using the risk assessment applied to the customer's structure.