Buying a home with live knob and tube wiring requires careful consideration. You don’t need opinions, you need facts.
The fact is that millions of homes still have knob and tube wiring, and there’s no solid evidence that it’s inherently more dangerous than other types of wiring when it’s in good condition. The biggest limitation is the lack of a ground wire, which certainly makes it less safe by modern standards, but not automatically unsafe or dangerous. Installing GFCI breakers or receptacles can mitigate most of the shock risk.
While the wiring itself isn’t dangerous, homeowners kind of are. Nearly all of the risk associated with knob and tube comes from improper alterations: amateur splices, overloaded circuits, or mixing modern wiring methods with old ones. A thorough inspection can catch some of this, but the reality is that not all wiring is visible.
There are practical issues as well. Homeowners insurance can be difficult or expensive to obtain, and some carriers won’t insure homes with active knob and tube at all. Adding modern electrical loads to these circuits can be challenging or impossible, although an updated electrical panel does allow you to add new, modern circuits alongside the old ones. Building codes also prohibit insulating over active knob and tube wiring, which can make it difficult to properly insulate large portions of the home.
In rare cases, the wire insulation deteriorates or falls off entirely, leaving exposed live conductors. That’s obviously dangerous and requires immediate correction, but it’s not the norm.
In the hundreds of times I’ve encountered knob and tube wiring, the vast majority has been in good condition and functioning exactly as intended. It’s old, outdated, and limited, but often stable.
Final thoughts: Knob and tube isn’t automatically a deal-breaker, nor is it something to ignore. It’s a system that demands context: condition, modifications, insurance implications, and long-term plans for the home. If you understand its limitations, verify its condition, and plan for eventual upgrades, it can be managed safely, but it’s rarely ideal and almost never future-proof.
