knob-and-tube
Isaac Kremer/ November 23, 2025/ / 0 comments
An electric wiring system used in concealed spaces; wires are threaded through insulated tubes at joists and studs and are held along the surface of members by insulating knobs; typically made of porcelain, but also included glass and pottery. See also electric wiring, porcelain cleats. (Bucher, 1996)