ELECTRICAL
4 min read
Knob-and-tube wiring: risks and options
Common in homes built before the 1940s, knob-and-tube wiring isn’t automatically dangerous, but it has real limits.
What it is
Knob-and-tube wiring runs single wires through ceramic knobs and tubes in walls and attics. It was common in homes built before the 1940s.
Why it’s a concern
- No ground wire
- Not designed for modern electrical loads
- Insulation on the wire becomes brittle with age
- Often modified or spliced over the decades
- Should not be buried in thermal insulation
Insurance and home sales
Many insurers ask about knob-and-tube wiring, and it often comes up in home inspections. Replacement is sometimes a condition of coverage.
Options
Rewiring can be done all at once or in phases, starting with kitchens, bathrooms, and laundry areas where loads are highest.