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What You Should Know About Knob & Tube Wiring

If you’re the owner of an older home, or if you’re planning to buy one, you may already know that some older homes have knob and tube wiring – a wiring method used in residential homes in the early 1900s to 1940s. Knob and tube wiring is no longer installed and you may be surprised to find out that many insurers will not provide or renew coverage on homes with this type of wiring as they consider it to be a higher risk. Also, older electrical systems do not contain the same safety benefits found in modern electrical installations (for example, ground fault circuit interrupters in bathrooms and outdoor locations.) Some insurance companies even require a total replacement of knob and tube wiring prior to providing insurance coverage.

If your home has knob and tube wiring, the Electrical Safety Authority (ESA) recommends you have a Licensed Electrical Contractor check the “knob and tube” conductors in your existing installations for signs of deterioration or damage; or arrange to get a general electrical inspection. This is different than a home inspection because it is focused solely on the electrical. Based on the electrical inspection and/or review by a Licensed Electrical Contractor, it might be recommended that you replace the wiring to ensure the safety of you and your family.  

Myths and Facts about Knob and Tube Wiring

Myth:  Knob & Tube wiring is unsafe.
Fact:   Knob & Tube wiring is safe, provided it is properly maintained by a Licensed Electrical Contractor as outlined above.

Myth:  The Ontario Electrical Safety Code no longer recognizes knob and tube wiring as an acceptable wiring method, so all knob and tube wiring must be disconnected and replaced.
Fact:   The Electrical Safety Authority and the Ontario Electrical Safety Code (the Code) recognize and accept knob and tube wiring methods; however certain rules must be followed in order to ensure electrical safety. The Code contains rules that govern the installation of open type wiring methods such as knob & tube. Rules 12-200 to 12-224 set out the minimum safety standards for the installation of open wiring.

Learn more about knob and tube wiring in residential installations