Copper Wires And Tubes On The Ceiling
Some homeowners may see several wires stretching across their walls and ceilings. These are knob-and-tube wiring, an old method of electrical wiring that was common from the 1880s through the early 1940s.
Copper wires were protected by porcelain and nailed down with porcelain knob insulators.Although knob-and-tube wiring did the job, it had a high cost of installation compared to modern power cables. Currently, knob-and-tube installations are not permitted in the United States except in specific situations. If you’re lucky, you’ll stumble across a building that still has it.