The rural electrification drive during the New Deal led to a wide expansion in the number of jobs in the electric power industry.Many power linemen during that period traveled around the country following jobs as they became available in tower construction, substation construction, and wire stringing. They often lived in temporary camps set up near the project they were working on, or in boarding houses if the work was in a town or city and relocating every few weeks to months.
The occupation was lucrative at the time, but the hazards and the extensive travel limited the appeal. A brief drive to electrify some railroads on the East Coast of the U.S.led to the development of specialization of linemen who installed and maintained catenary overhead lines.
Growth in this branch of line work declined after most railroads favored diesel over electric engines for replacement to steam engines. The occupation evolved during the 1940s and 1950s with expansion of residential electrification.
This led to an increase in the number of linemen needed to maintain power distribution circuits and provide emergency repairs.
Also during the 1950s, some electric lines began to be installed in underground tunnels, expanding the scope of the work.Źródło: https://en.wikipedia.org/wiki/Lineman_%28technician%29
The first interior power wiring systems used conductors that were bare or covered with cloth, which were secured by staples to the framing of the building or on running boards.Where conductors went through walls, they were protected with cloth tape. Splices were done similarly to telegraph connections, and soldered for security.
Underground conductors were insulated with wrappings of cloth tape soaked in pitch, and laid in wooden troughs which were then buried.
Such wiring systems were unsatisfactory because of the danger of electrocution and fire, plus the high labour cost for such installations.Źródło: https://en.wikipedia.org/wiki/Electrical_wiring.