Plenty of charming older homes in Wenatchee, Cashmere, and Leavenworth were built with knob-and-tube (K&T) wiring. If you own one — or you're buying one — it's worth understanding what K&T is and when it becomes a problem.
What is knob-and-tube wiring?
K&T was the standard method of wiring homes from roughly the 1880s into the 1940s. It uses ceramic knobs to anchor wires and ceramic tubes to pass them through framing. The wiring itself isn't inherently 'live dangerous' — but it was designed for a very different era of electrical use.
Where the real risks come in
- •No ground wire — K&T is a two-wire system, so it can't safely serve modern three-prong appliances and electronics.
- •Brittle insulation — after decades, the original insulation can crack and crumble, exposing conductors.
- •Buried in insulation — K&T was designed to dissipate heat in open air. When later owners add blown-in attic insulation over it, it can overheat.
- •Amateur modifications — many problems come from decades of unpermitted splices and add-ons, not the original wiring.
What it means for insurance
This is often the deciding factor. Many insurers won't write or renew a policy on a home with active knob-and-tube wiring, or they charge significantly more. If you're buying, your lender or insurer may require remediation.
Do you have to rewire everything?
Not always. An electrician can assess how much active K&T remains and whether a partial or full rewire makes sense. Many homeowners phase the work, starting with the highest-risk circuits.
Wondering about your home's wiring?