EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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Yes, old knob and tube wiring can contribute to house fires, and this is one of the main reasons it draws so much attention from home inspectors, insurers, and electricians alike. That said, the risk is not automatic or uniform across every home that has it. Here is what actually makes knob and tube wiring risky, and what determines how much danger it poses in your specific home, from the licensed electricians at EZSMART, serving Toronto and the GTA.
Knob and tube wiring was standard in North American homes roughly from the 1880s through the 1940s. It uses ceramic knobs to support wires as they run along framing, and ceramic tubes to protect wires passing through joists and studs. The individual wires are not bundled in a protective sheath the way modern wiring is, and the system has no ground wire.
Not necessarily. A knob and tube system that has been well maintained, is not covered in insulation, has had no unsafe modifications, and is not carrying more load than it was designed for can be functioning acceptably. The real risk comes from the combination of age, hidden damage, and modern electrical demand that was never part of the original design. This is exactly why a professional assessment matters more than assumptions based on age alone.
Insurance is a major driver here. Many Ontario insurers require knob and tube wiring to be inspected or replaced before providing or renewing coverage. Work involving knob and tube wiring should always be performed by a licensed electrician, in accordance with Electrical Safety Authority standards.
How do I know if my home has knob and tube wiring?
A licensed electrician can confirm this quickly by checking your panel and accessible wiring, often in a basement or attic.
Do I have to fully replace knob and tube wiring?
Not always immediately, though many insurers and electricians recommend it, particularly for circuits under heavy use or covered in insulation.
Can I keep knob and tube wiring if it still works fine?
It may continue to function, but working does not mean it meets current safety standards. A professional assessment can clarify your specific risk level.
How much does it cost to replace knob and tube wiring?
Cost depends on how much of the home is affected and accessibility. A licensed electrician can assess your home and provide a quote.
Have knob and tube wiring in your home? EZSMART provides licensed assessments and replacement across Toronto and the GTA. Call 416-838-9006, and see what our customers say on our Google reviews page.
