Knob and Tube Wiring


Licensed Commercial & Residential Electrician

Houses built before 1950 were wired with a system known as ‘knob and tube’ or ‘ungrounded’. Knob and tube wiring is so dangerous that a lot of insurance companies won’t even cover buildings that use it. If your home or business uses this unsafe method, it is crucial that you get a professional electrician to replace it as soon as possible. Besides being unsafe, it is also violates the legal electrical codes of today. If you have knob and tube wiring in Toronto, call Best Electrician immediately for a consultation.

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But why is knob and tube wiring so dangerous? Well: 

1. There Is No Grounding Wire

There are only two wires in an ungrounded system: the neutral wire and the hot wire. Modern wiring uses a grounding wire as well that sends electricity safely into the ground when there is a surge or fault. Because excess electricity doesn’t have anywhere to go without a ground wire, it makes the possibility of shocks and electrical fires much more likely to happen. In addition, the on/off switch for the circuit was usually placed on the neutral wire, letting current continue to flow through the hot wire. 

2. The Sheathing on the Insulation Breaks Down Easily

Both the sheathing and the insulation can disintegrate over time quite easily. Since knob and tube systems are already in old buildings, it’s a recipe for disaster. The wiring today uses better, safer materials that are much less likely to catch fire. Best Electrician will know just what to use for sheathing and insulation instead, so contact them today if you need a knob and tube wiring removal in Toronto. 

3. Knob and Tube Wiring Uses 15-Amp Wires with a 60-Amp Power Supply

You may be able to tell where this is going. If 60 amps of energy regularly flows into your home through the electrical panel, but the wiring in your house can only handle 15 amps, it means more power is traveling through the wires than is safe. Especially without a grounding wire, it greatly increases the chance of an electrical fire. It will also generate a lot of heat. 

4. Electronics Today Are More Demanding

In order to get the electricity to the devices that need it, many modern electronics require high ampacity loads. (Ampacity stands for “amperage capacity” and is simply a measure of how much electric current a device or conductor can carry before deteriorating.) The extra loads can make the insulation brittle which exposes the wire. The wire is likely to get overheated because of the extra electrical load and that can lead to fires. 

5. Knob and Tube Wiring Uses Two-Prong Outlets

Two-pronged outlets are a nuisance. It’s annoying when you can’t plug in large appliances without getting converters, but did you know that two-pronged outlets are also a sign that your house is using a knob and tube system? Without a ground wire, the risk of injury and shock skyrockets, especially in rooms where water might be lying around like bathrooms and kitchens. If your commercial building or home was built prior to 1950, then it is extremely likely that it has this kind of wiring. Knob and tube wiring could harm you, your family, or your employees, so it is not something that should be taken lightly. Fortunately, it is sometimes possible to replace the knob and tube system without rewiring the entire building, since that can be expensive. Especially since most insurance companies don’t cover buildings with old wiring, it’s crucial that you update as soon as possible. And, if you are planning on selling your home or business, you may find it difficult to do if your potential buyer cannot get insurance. Knob and tube wiring is inherently dangerous, and requires professional assistance to solve the problem. While knob and tube used to be cutting-edge technology, those days are long in the past. Best Electrician can get you up-to-date by answering any questions you may have about knob and tube wiring in Toronto.

Other Sources of Damage

It’s not always the knob and tube wiring itself that is so dangerous. In an old house, lots of other factors have had time to take their toll on your electrical system. Amateur alterations to your wiring can be extremely dangerous, since things could be improperly connected. Often, people add more wires to the original knob and tube system, causing the fuses protecting the old circuits to blow out a lot. That causes people to buy larger fuses to stop the circuits from breaking, but that is just plain unsafe. Overloading the wires will make them brittle and they will disintegrate.

Heat degrades the insulation on the wires, and even household pests like squirrels or bats might decide your wiring insulation is a tasty treat. Thermal insulation can also exacerbate the problem, since the heat from the wiring can easily catch it on fire. Knob and tube was originally designed with lots of space around the wires where heat could dissipate. Placing insulation right next to the wiring is a significant hazard.

Does all of this information feel overwhelming? If you have any questions about a knob and tube system in Toronto, call Best Electrician and let us deal with it so you don’t have to think about it anymore.

Do I Actually Have Knob and Tube Wiring?

Maybe you’re getting a little nervous that your house uses knob and tube and you didn’t even realize it. Maybe you have two-pronged outlets. However, it is better to check first before starting to worry.

Tube wiring is most visible in the attic or basement, so inspect any wiring that you can find. In the attic, you may need to move some insulation in order to clearly see the wires. Be careful, as there are hidden wires that could break if you step on them. In the basement, you can just look up at the floorboards of the main floor. Wires that are connected to small pieces of ceramic is a sure sign that your house or business uses a knob and tube system. Remember that you will see only two wires, since there will be no grounding wire.

If the wiring is not accessible from the attic or basement, you’ll need to look inside the electrical panel that houses all the circuit breakers. However, it is best to call a professional at this point in the process, because there could be live wires in the electrical panel, and a shock could be fatal. Even when the main power source is switched off, there will still be live wires where electricity enters your business or home.

Once you can see into the circuit box, you may notice that the wires that have only two strands. That probably means you have knob and tube wiring.

Even in an updated home, there may be certain circuits that still have knob and tube wiring. The best thing to do is call a professional to inspect to your house or business to look for any dangerous two-stranded wires. A professional electrician will also provide an estimate as to how much it will cost to get the wiring replaced. For knob and tube wiring in Toronto, call Best Electrician for a consultation and inspection.

How Much Will a Replacement Cost Me?

If you need a knob and tube replacement in Toronto, your best option is to work with Best Electrician. Since the process can be quite costly, you’ll feel better knowing that you are working with someone who has your best interests in mind and will get you the best price around. Our electricians will also break the total cost down for you, since there may be separate charges for running new circuits or replacing fuses. The cost is worth it, too. Your house or business will be much safer and you will be able to obtain insurance.

Don’t Some Companies Insure Buildings With Knob and Tube Wiring?

Since knob and tube wiring does not use a grounding wire, it is exceptionally difficult to get insurance for any building that uses it. Without insurance, it will be impossible to obtain a mortgage. If you are looking into buying a house, checking the wiring should be a top priority.

There is something you can do to make your building safer without a full replacement. Adding a ground fault circuit breaker to the circuits that use knob and tube vastly increases safety.

However, if you can’t make a deal with an insurance company, the knob and tube wiring is going to need to be replaced. If you are the one trying to buy, let the seller know that you will not make the purchase without a replacement so that they can get started.

Even if you do manage to convince an insurance company to cover a building with unsafe wiring, it will probably cost a lot more. Many companies will agree to cover you as long as knob and tube wiring is replaced within 30 days. If you need a knob and tube removal in Toronto, look no further than Best Electrician. Our highly-trained electricians can help you efficiently and economically.