Knob and Tube Wiring

Knob and tube wiring was an early method of electrical wiring in buildings commonly used in the United States from the 1880s to the 1970s.

It consisted of single-insulated copper conductors wired within walls or ceiling cavities and passing through stud drill-holes. The main problems with knob and tube wiring are: there is no electrical ground; they may be too close to insulation, which could cause fires; and they may be damaged by age, exposure to leaks, and chewing rodents.

Knob and tube wiring still may be functional in a home. The original concept of the wiring was a safe method. Although knob and tube wiring may not need to be replaced, it is a good idea for homeowners with knob and tube wiring to have their home carefully inspected by the professionals at Wire Nutz Electric. Knob and tube wiring could be made safer by adding GFCIs/AFCIs, using small light bulbs or LED bulbs which produce less heat, and insulation checked to make sure it’s far from the wiring.

Because knob and tube systems lack an electrical ground, may have damaged insulation, or may have been improperly modified or extended, it is in the homeowners’ best interest to possibly replace or repair the wiring.