Is Knob-and-Tube Wiring Safe in My Home?
Knob-and-tube was standard in homes built before the 1950s. Intact and untouched it can be stable — but insurers flag it, and modern loads expose its limits.
- Author
- By Cabrillo Plumbing, Heating & Air
- Last updated
- Updated June 2026
- Reading time
- 4 min read
Knob-and-tube (K&T) wiring isn't automatically dangerous, but it has no ground wire, its insulation gets brittle with age, and it's easily damaged by later renovations or by being buried in insulation (which makes it overheat). Many insurers won't cover homes with active K&T. If yours is original, the safe move is an assessment — and usually a phased replacement as part of a panel upgrade.
What to know
- K&T has no ground — a problem for modern appliances and surge-sensitive electronics.
- Buried-in-insulation K&T can overheat; renovations often nick or splice it unsafely.
- Insurance and point-of-sale inspections frequently flag active K&T.
- Replacement usually pairs naturally with an electrical panel upgrade.
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