What is knob-and-tube wiring?
Knob-and-tube wiring is an early electrical distribution method that runs individual copper wires through ceramic insulators mounted on wooden frames, typically found in homes built before the 1950s. It is now considered unsafe and unreliable by modern standards.
Knob-and-tube wiring consists of single copper conductors run through air and supported by ceramic knobs nailed to framing members, with cloth-wrapped insulation that becomes brittle with age. This method dominated residential electrical systems in Spartanburg homes built in the early 1900s through the mid-20th century, before the adoption of sheathed cable and modern wiring practices.
The system is visually distinctive: you will see ceramic knobs along attic joists and wall cavities, with cloth-covered wires threaded through porcelain tubes where they pass through framing. Over decades, the cloth insulation deteriorates, exposing bare copper and creating shock and fire hazards.
Insurers flag knob-and-tube installations as a major liability concern. The wiring lacks a ground conductor, leaving appliances and occupants vulnerable. It was never designed for modern electrical loads, so older systems frequently overheat under typical household demand. Additionally, the absence of a protective outer jacket means squirrels, rodents, and water damage can damage conductors directly. Many homeowners insurance policies in Spartanburg will not cover properties with active knob-and-tube wiring, or require immediate replacement as a condition of coverage.
If you own a pre-1950s Spartanburg home, a licensed electrician can inspect your panel and attic to confirm whether knob-and-tube is present and recommend whether rewiring is needed. Residential electricians in the area routinely evaluate and upgrade these systems to meet current safety standards.