Knob & Tube Wiring

What to do when buying, selling, insuring or renovating a vintage home?

Knob and Tube removal and replacement is one of our specialty services.

We are often asked to quote and/or provide consultation on remediation options for customers with or about to acquire vintage property with this outdated wiring system.

There are two opposing points of view to safety and serviceability of this circa 1900 to early 1940's wiring system: The Insurance Industry and the Electrical Safety Authority (ESA) (Ontario).

The challenge is to satisfy both.


ESA Position

In order to understand what it is, ESA has issued an excellent bulletin (attached) that provides a technical overview, the code requirements as well as the benefits of new wiring vs. this system. ESA will pass and issue an inspection certificate on knob and tube wiring that has been altered as follows:

  • Removal or replacement of exposed knob and tube wiring or wiring that has been altered, spliced or changed.
  • Removal of all major loads from knob & tube circuits.
  • Grounding or ground fault protection of all receptacles remaining in service.
  • Install approved steel boxes at receptacles, switches and light fixtures where they were originally absent.


Insurance Industry Position

Most insurance underwriters have taken the position lately that all knob and tube wiring must be replaced.  Although a few insurance companies will, under some circumstances, accept the ESA inspection certificates for code compliant knob and tube.

We are finding now that just a very few insurers left that will accept code compliant knob and tube.  Soon there will be no insurance or mortgage companies that will underwrite any vintage homes with knob and tube wiring.


Our Recommendation:

Although we have supported and promoted the ESA alterations in the past, we are now convinced that it is time to do a complete removal and rewire to present day standard to protect your investment.

The ESA Code is a minimum electrical requirement and the Insurance Underwriters are taking a forward visioning risk management position.

We have, therefore, adopted the position that full removal is the best option in most situations for the future.


What does it cost?

Most replacements take 2 to 5 days for two or three tradesmen plus materials plus the cost of the ESA electrical inspection on completion.

When you call for a site inspection and proposal, we will estimate the extent of the replacement and determine your potential financial commitment. (most rewires fall between $2500 and $8000 plus HST)


No Holes ....Non Intrusive !

Our tradesmen have been doing Knob and Tube removals for years and have developed a number of special tools and methods that nearly always avoid the necessity for opening any holes in your walls or ceilings.

Power is restored to all circuits at the end of each day, so you have electrical service each evening during the rewire.

Our tradesmen are aware of the importance of cleanup each day and incorporate this into our workdays. (We are often complimented on how tidy our knob and tube job sites are maintained.)


ESA inspects and issues their certificate within days of completion.


For a free consultation or estimate call ..519-647-3337..We serve the Cambridge, Hamilton, Brantford, Dundas, Ancaster, Flamborough, Haldimand Norfolk, Burlington and Waterdown areas in Ontario.

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