Knob & Tube Wiring

Distinctive ceramic tubes passing through the wood structure and ceramic knobs used to change direction give this old two-wire system its name. Knob and Tube wiring was in use for roughly thirty-years from the 1920’s –50’s.

In this system wire joints or splices as they are known are made in the open air. The wire is twisted together, soldered and then wrapped in tape as seen just in front of the ceramic knob. Today all wire connections are made within junction boxes to protect the splices and reduce fire hazards.

It is also an ungrounded, two pronged, system not appropriate for many of todays, three pronged, appliances and electronics.

Years of wear, modifications, and renovations around this type of wiring system have generally compromised its integrity.

Some home insurers will not write new policies on homes with extensive knob and tube wiring or charge a higher premium due to higher fire hazard risks.