Which type of wiring was commonly used in residential construction before the 1950s?

Knob-and-tube wiring is a type of electrical wiring that was commonly used in residential construction before the 1950s. This system consists of insulated copper conductors that run through tubes and are supported by ceramic knobs. It was one of the first methods to safely distribute electricity in homes and was prevalent due to its affordability and the relative availability of materials at the time.

The historical context of knob-and-tube wiring reflects the early standards of electrical safety and installation practices. While this type of wiring has largely fallen out of favor due to updated safety codes and the introduction of more efficient wiring methods, understanding its widespread use provides insight into the evolution of electrical systems in residential properties. This knowledge is important for real estate professionals as they assess older homes and advise clients on safety and potential upgrades.

In contrast, Romex wiring, used widely after the 1940s, is not characteristic of pre-1950s construction, while fiber optic wiring is a modern innovation developed in the latter half of the 20th century. Metallic conduit wiring, although used earlier, was not as commonly found in residential settings compared to knob-and-tube during that era.