Knob-and-tube was used in Canadian homes during the early twentieth century. Its presence, extent and condition cannot be confirmed from a home's age or one visible wire. Buyers need property-specific information from a Licensed Electrical Contractor, insurer and other professionals before deciding how the electrical system affects an offer.
By Zach Boulert, REALTOR® / Sales Representative · ·
Understand what the term does—and does not—tell you
The Electrical Safety Authority's knob-and-tube guidance describes it as a wiring method used in homes from the early 1900s into the 1940s. ESA also explains that the current Ontario Electrical Safety Code is not retroactive. The practical issue is therefore not simply whether the system is old, but what is present, how it has been maintained or altered and what qualified professionals and the insurer require.
A listing age, fuse panel or piece of visible wiring is not a complete assessment. A house may contain original circuits, later rewiring and renovations from several periods. Ask for invoices, permits, ESA records and any electrical reports, but treat documents as part of the file rather than proof that unseen work is in satisfactory condition.
Make three calls before the offer deadline
First, discuss the exact property with an insurer or broker and ask what information they need to quote and bind coverage. ESA notes that some insurers may not provide or renew coverage when knob-and-tube wiring remains, and some may require replacement. Requirements vary, so do not rely on what happened with another house or insurer.
Second, ask a Licensed Electrical Contractor about an assessment and the questions they can answer. Third, discuss inspection scope with an experienced home inspector. RECO's inspection guidance identifies electrical systems among the major systems an inspector examines, while ESA says an LEC's electrical assessment is different because it focuses specifically on the electrical system.
Ask about extent, condition and alterations
Useful questions include: Which circuits appear to be knob-and-tube? Has insulation been added around wiring? Are there signs of deterioration, damage or improper alterations? Which areas have modern grounded wiring? What supplies kitchens, bathrooms, exterior receptacles and major appliances? Do not inspect live components yourself or ask an unqualified person to certify safety.
If replacement is recommended or required, obtain a written scope from a Licensed Electrical Contractor. Ask what access, wall repair, permits, ESA notifications and follow-up work the estimate includes. A broad allowance based on square footage is not a substitute for examining the actual house.
Connect electrical findings to financing, timing and the offer
Electrical uncertainty can affect insurance availability, lender requirements, closing readiness, renovation timing and the buyer's reserve. Review those pieces together before setting a price or condition strategy. A seller's willingness to provide access or documents may matter as much as an informal repair estimate.
RECO's buyer checklist recommends investigating the age and condition of electrical and plumbing systems and, where possible, using appropriate offer conditions. Work with your REALTOR®, lawyer, lender and insurer to decide what protection fits the transaction rather than copying conditions from another offer.
Treat wiring as one part of the older-home decision
Electrical work should not absorb the entire due-diligence plan. Use the 12-point guide to buying an older London house to review plumbing, drainage, foundations, roofs, heating, insulation, renovations, permits and heritage questions alongside the electrical system.
This is especially relevant when comparing older properties in Hamilton Road and Old East Village. Neither neighbourhood name establishes the wiring type or condition. The exact house, records and professional assessment control the decision.
Official sources and address checks
Use current ESA guidance and an ESA-licensed electrical contractor for property-specific electrical questions. Use RECO's buyer and inspection resources for offer-planning context. Confirm insurance and lending requirements directly with the providers involved in your purchase before waiving conditions.
Zach Boulert is a REALTOR® and Sales Representative with RE/MAX Icon Realty Brokerage serving London and Middlesex County. Call 647-877-3792 or use the form below with the address, MLS® number or listing link so Zach can help organize access, documents, timing and questions for qualified professionals.
Knob-and-tube wiring questions
Is knob-and-tube wiring automatically illegal in Ontario?+
ESA states that the current Electrical Safety Code is not retroactive. The actual system, condition, alterations and any required work must be assessed for the property by qualified professionals.
Will every insurer cover a house with knob-and-tube wiring?+
No. ESA notes that some insurers may decline or require replacement. Ask insurers about the exact property and their current underwriting requirements.
Can a regular home inspector approve the electrical system?+
A home inspector can examine visible major systems within the inspection scope. ESA distinguishes that from an assessment by a Licensed Electrical Contractor focused on the electrical system.
Should I get a replacement estimate before offering?+
When replacement may affect insurance, financing, budget or timing, seek a property-specific written scope early enough to inform the offer and conditions.
Found a London home with possible older wiring?
Enter the address, MLS® number or listing link so the insurance, inspection and electrical questions can be organized before the offer deadline.
Ask about this home’s wiringThis is general real estate information, not an electrical inspection, safety certification, insurance opinion or cost estimate. Use a Licensed Electrical Contractor and other qualified providers.