Knob And Tube Wiring In Calgary Homes

Last week I showed a home in the inner-city that was built in the 1920’s.  Upon going to the basement we quickly discovered that the home still had knob and tube wiring in places.


Knob and tube wiring, also known as open wiring, was used starting in the early 1900’s until approximately 1950.   It gets its name from the ceramic knobs and tubes that secure and protect the wire as it passes through floor joists as seen in the picture I took above.

Experts have differing opinions on the safety of such wiring and it may not be necessary to replace it as a matter of course.   I’m not an electrician so I will not weigh in on this issue – that’s for you to decide after talking to a qualified expert.

However, what you need to be aware of is even if the knob and tube wiring is deemed as safe and well-maintained, many insurance companies will not offer coverage at all if your home contains this type of wiring.   Other insurance companies will only insure it after they have it inspected.    Some may agree to insure but then refuse to renew the policy down the road until you upgrade the wiring.

Since your lender will not fund the mortgage without insurance on the home, this could cause difficulties come closing day.

When making an offer on a home that contains knob-and-tube wiring, be sure to include a condition on being able to obtain insurance for the home.

For more information on knob-and-tube wiring, you can read the ESA’s bulletin:  click here to download

Questions? Ready to buy or sell real estate? I can be contacted at or 403-554-2284

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