What Is Required to Install Ground Wiring in a House Built Challenges. The hardest part of rewiring a 1950s home to include ground wiring is the fishing of the new, nonmetallic sheathed cable through the finished walls, floors and ceilings. History of Old electrical wiring identification: photo guide History of electrical wire & electrical wiring: how to recognize knob and tube electrical wiring and unsafe "extension cord" wiring. How to evaluate the number of electrical circuits in an older home. Photo guide to types of old building electrical wires. These photos help identify types, condition, & hazards of old electrical wiring in buildings. What is the life expectancy of electrical wiring in a house? Plastic wire insulation with good resistance to thermal deterioration followed next in the mid-1950s, and the formulation of the plastic was upgraded in the 1980s for better heat resistance. The newer wiring is expected to have a lifespan of 80 years or more. only time will tell. A Brief History of Home Electrical Wiring - The Spruce In the 1920s to 1940s, electrical installations took a turn to a more protective wiring scheme—flexible armored cable. Flex, also known as Greenfield, was a welcomed addition to home wiring because the flexible metal walls helped to protect the wires from damage, and also offered a metal pathway that could ground the system when properly installed.