Knob-and-Tube Wiring — Is It Still Safe?

Just last week I was up in the cramped attic of a 1973 split-level on Plains Road, flashlight in hand, when I spotted something that made my heart sink. Two white ceramic knobs mounted on a beam with old cloth-wrapped wire stretched between them like some museum display. The homeowner had no idea this dinosaur electrical system was still lurking above his family room. You could smell that dusty, old insulation mixed with something slightly burnt.

Now here's what most people don't understand about knob-and-tube wiring. It wasn't actually terrible technology for its time. I've seen installations from the 1920s that still function, though I'd never recommend keeping them.

The real problem isn't the age, it's what happens when you try to make a 1920s electrical system carry the load of a 2025 household. Think about it - when knob-and-tube was installed, homes had maybe ten electrical outlets total. No dishwashers, no central air, no home offices packed with computers and monitors.

What I find most concerning is how often I discover knob-and-tube that's been partially updated by homeowners who didn't know what they were doing. Last month in Tyandaga I found a house where someone had spliced modern Romex cable directly into the old cloth wiring. That's a fire waiting to happen. The insurance adjuster I work with says these hybrid systems are responsible for more claims than pure knob-and-tube installations.

Here's something that might surprise you. In Burlington, I still find active knob-and-tube in about fifteen percent of homes built before 1950. Some of these houses in the downtown core have been on the market three times in five years because buyers keep walking away once they get the inspection report.

The financial reality hits hard. Complete rewiring for a typical 1,200 square foot bungalow runs between $12,400 and $18,650 depending on how much drywall needs to come down. Add another $3,200 if you need to upgrade the main panel to handle modern electrical loads. I always tell my clients to budget for the higher end because there's always something unexpected once the electricians start opening walls.

But here's where buyers make their biggest mistake. They think they can live with knob-and-tube "for a few years" and update it gradually. In my fifteen years doing this job, I've never seen that approach work out well. Insurance companies are getting stricter every year about covering homes with old wiring. Some won't touch it at all.

The technical issues go beyond just capacity. Knob-and-tube systems don't have a ground wire, which means no protection against electrical faults. Modern appliances expect three-wire connections, and when you don't have them, you're asking for trouble. I've seen refrigerators, washers, and microwaves fail prematurely because they can't properly ground electrical surges.

Safety aside, there's the practical headache of living with inadequate electrical service. You'll find yourself constantly tripping breakers, unable to run the coffee maker and toaster at the same time. Forget about adding that workshop in the basement or upgrading to electric vehicle charging.

I was in Aldershot three weeks ago looking at a beautiful 1940s Cape Cod that had been lovingly maintained everywhere except the electrical. The sellers had invested $40,000 in a new kitchen but couldn't understand why potential buyers kept offering $25,000 under asking. When I showed them the cloth-wrapped wiring feeding their gorgeous new induction cooktop, it finally clicked.

The inspection process for knob-and-tube is methodical but time-consuming. I check every accessible junction, look for signs of overheating, and test what I can reach safely. The real challenge comes in attics where insulation has been blown over the old wiring. Knob-and-tube needs air circulation to dissipate heat, and when it gets buried under modern insulation, it becomes dangerous.

Spring weather in April 2026 should make attic inspections more comfortable, but I'll still be crawling through spaces that haven't been disturbed in decades. The dust and debris up there tells the story of every renovation and repair over the past century.

What really frustrates me is when sellers try to hide electrical issues. I've had agents tell me the knob-and-tube is "decorative" or "disconnected" when it's clearly carrying live current. My electrical tester doesn't lie, and neither do I. These games just waste everyone's time and create liability issues down the road.

The replacement process isn't as disruptive as most people fear. A good electrician can rewire most homes in three to five days with minimal wall damage if they plan the routes carefully. Yes, you'll have some patching and painting afterward, but it's manageable with the right contractor.

For homes in Burlington's older neighborhoods, upgrading from knob-and-tube actually adds value beyond the safety benefits. Modern electrical systems support home automation, efficient heating and cooling, and the kind of technology integration that today's buyers expect. I always remind my clients that they're not just fixing a problem, they're investing in their home's future marketability and their family's safety.