What is Knob and Tube Wiring?

understand what is knob and tube and the different between other house wiring

What kind of wiring does your house have? The answer to this question will largely depend on the year of its construction. While older homes are often renowned for their abundance of character and sturdy construction, if you own a home that was built before the 1950s, you probably have what is known as knob and tube wiring (also known as K&T).

It’s easiest to explain what K&T wiring is by comparing it to the wiring that is used in modern homes.

Most modern homes use what is known as non-metallic, or NM. This wiring type consists of two or three wires bound together in a protective sheathing. This sheathing, which will contain at least one live wire and one ground wire, is made out of plastic and is resistant to incredibly hot temperatures.

K&T wiring features a protective casing too, but instead of plastic, it is made out of rubber. The rubber casing makes it more susceptible to high temperatures, meaning that it can be worn down quite easily and need to be replaced. If it is not replaced, it can pose a serious hazard of an electrical fire.  It does not contain a ground wire, which means that it cannot be used in bathrooms or kitchens as there is a heightened risk of electrical shock.

Due to this hazard, some home insurance companies may charge homeowners with home and tube wiring a premium, or flat out refuse to insure them at all. The hazard is especially amplified if the K&T wiring is run through an enclosed space, such as through installation. Some electricians will even make a point of calling K&T wiring “open wiring” to emphasize the fact that this wiring needs to have its own open space.


Does K&T Wiring Need to Be Replaced?

There is technically nothing in the Canadian building code that states that K&T wiring must be replaced. However, if you think that means that you can just carry on with K&T wiring, read on.

As we mentioned earlier, knob and tube wiring can overheat and pose a fire hazard. It can also give you high insurance rates or disqualify you from keeping any kind of insurance at all. There are other concerns to have on top of this, such as the fact that knob and tube wiring elevates the risk of electrical shocks for home residents, as well as makes it impossible to plug in three-prong plugs (which the majority of modern electronics use).

If you are considering the purchase of a home with K&T wiring, make sure that you get the wiring inspected by a professional before you go through with the home purchase. While it is not required by law that a homeowner have their K&T wiring replaced, it is highly recommended that they invest in regular inspections and maintenance in lieu of a full replacement should they choose to go that route.


How Much Does K&T  Wiring Replacement Cost?

It is hard to provide a blanket estimate for the cost of replacing K&T wiring, as this will depend on many individual factors. If you are buying a house with K&T wiring, you may want to make the cost of the wiring’s replacement a conditional part of your offer. You can then get a licensed electrician to provide a quote for you.


Looking for Electrical Companies in Lower Mainland?

Our knowledgeable staff is here to help you with a wide range of electrical issues, including emergency services. When it comes to the wiring of your home or business, you will want to trust the professionals who are at the top of their game. Reach out today to Surrey electrical company to see how we can help you.