Knob-and-tube wiring was widely used in homes in the United States until what year?

Knob-and-tube wiring was a common method for electrical wiring in homes across the United States from the late 1800s until around the 1930s. This type of wiring consists of insulated copper conductors supported by ceramic knobs and run through tubes for protection, which was quite effective for its time.

As electrical standards evolved and the demand for greater electrical capacity increased, newer wiring methods emerged that enhanced safety and efficiency. The incorporation of grounding wires and more advanced insulation materials led to the decline of knob-and-tube wiring's popularity. By the late 1930s, it was largely replaced by more modern wiring techniques that addressed electrical loads and safety concerns more effectively.

Therefore, 1930 stands as a pivotal year marking the end of widespread installation of knob-and-tube wiring in homes, aligning with the decline in its use due to advancements in electrical standards and practices.