alt Hacker NewsIn Victorian London, electricity was distributed around the home using bare wires with an air gap. It was 32v though.
Later it was superseded with lead wrapped in paper, until the Knob and Tube system. This comprised of single-insulated copper conductors installed within walls and ceilings, this wiring was encased in porcelain insulating tubes with cloth-lined sleeves.
One knob for Live and one knob for Neutral. The wires were held in place by porcelain knobs nailed to the house frame. Where wires passed through wood framing, they were threaded through porcelain tubes to prevent them from contacting the wood.
My house once had knob and tube wiring. Over the past 15 years I have replaced most of what I assume is the second-generation cloth-covered wiring (which dates back to the 40s, 50s, and 60s). Every once in a while, I come across the insulators from an older electrical system, but most of the wire that went with those insulators was pulled out long ago. The only remains are short bits of wire that were wrapped around the insulators.