knob-and-tube

adjective1

1. •
   Of or pertaining to a type of electrical wiring consisting of insulated conductive copper wire affixed by porcelain hardware and protected in vulnerable areas by insulated cloth sleeving. Widely used in North America during the late 19th and early 20th centuries.

   • If living in a house with antiquated knob-and-tube wiring—individual wires, not cables, passing through porcelain insulators—live wiring can be detected with a magnetic compass whose needle deflects — 1993