Knob and Tube Wiring Knob-and-tube (also known as K&T) was commonly used in buildings in North America from about 1880 to the 1940s. This system is considered obsolete and can be a safety hazard. In knob-and-tube wiring, individually conducting wires protected by rubberized cloth fabric are installed in stud and joist cavities, held in place [...]

Knob and tube wiring technique were one of the first standardized wiring systems. It was used before the 1940s and it used a single conductor usually insulated with a cloth fabric. Different types of porcelain insulators were used to separate the conductor from the wood in homes. Porcelain cylinders were inserted in holes to pass [...]