Applies to operation, installation, maintenance and extension of overhead and underground lines and service connections. Includes line installation within a building. Also includes the installation of fiber optic lines requiring specialized connection skills. Includes clearing of right of ways, the erection of poles, cross arms and insulators when performed in conjunction with installing telecommunication lines. Applies to laying of telephone cable by a specialist contractor under contract with a telephone company. Includes mechanical fusion splicing of fiber optic strands.