Knob and tube wiring is an electrical wiring method that was practiced from the 1880’s to the 1930’s. The method is achieved by running a single conductor wire. The wire is secured with a porcelain insulator and covered with a porcelain sleeve where it passes through a stud. Connections are made by twisting the wires, soldering together, and securing with rubber tape. Knob and tube should not he covered by isolation. It needs to be exposed so the heat can dissipate from it.