What is Knob and Tube Wiring?

Knob and tube wiring was an early standardized method of electrical wiring used in buildings in the United States from about 1880 to the 1940s. It consists of single insulated copper conductors run within wall cavities, passing through joist and stud drill-holes via protective porcelain insulating tubes, and supported along their length on nailed-down porcelain knob insulators.

While knob and tube wiring was an improvement over previous wiring methods, it has some inherent flaws that make it unsuitable for modern electrical loads and potentially unsafe:

Dangers and Risks of Knob and Tube Wiring

There are several serious risks posed by aging and deteriorating knob and tube electrical systems:

Recommendations for Homes with Knob and Tube Wiring

If your home has original knob and tube wiring, experts strongly recommend fully replacing it with modern wiring to prevent hazards. Some tips:

While knob and tube wiring was important in the early electrification of homes, it does not meet today's electrical safety standards. Replacing outdated and potentially dangerous wiring greatly reduces fire and shock risks.