As an early standardized method of electrical wiring in buildings, knob and tube wiring is commonly used in North American and Canada since the 1930s. It consisted of a single-insulated copper conductor that runs within the wall or ceiling cavities passing through the joist and stud drill-holes via a protective porcelain insulating tube, all while supporting their length on the nailed-down porcelain knob insulators. If your home was built before the 1950s, and has never undergone a whole-house rewiring, then there is a pretty chance that you could have a wiring system known as knob and tube in your home. The knob and tube wiring is an obsolete wiring that can be dangerous for your home. The main difference between modern wiring and the old knob and tube wiring is that there is no ground wire. This type of wiring cannot accommodate any electrical items with three prolonged plugs, and the risk of shocks and fire is much greater. Another difference is the wire insulation. Modern wiring is insulated with plastic, while knob-and-tube uses rubber. The breakdown of the insulation over time on knob-and-tube wiring is often the reason it is replaced. It’s important to note that this is frequently the result of overheating or mechanical abuse.

So let’s know more about knob and tube wiring and why replacing it is as important as changing your tires after a while.

A common features of the knob and tube wiring is that it features a hot wire and neutral wire with no third ground wire. The insulated wires run through porcelain knobs as it weaves through the house and the knobs that hold the wire away from the structural components of the home are made of timber trusses and studs. The wiring is accompanied through a wooden component when necessary, in order to provide an extra layer of insulation and protection so that the wiring isn’t pressed directly against the wood. When newly implemented the knob and tube wiring did not feature high-draw appliances, as there were few household items that needed a ground. However, with time the demand for amperage rose and the knob and tube wiring were not capable of meeting the needs of the average home, which resulted in the wires becoming overheated and ending in fires. The issue was the insulation on the wiring that became frayed and degraded with time which resulted in bare wire arcing into hazards.

In the modern electrical wiring designs, a ground wire is safely siphons off the excess power of your system and redirects it harmlessly into the ground. Nevertheless, without a ground wire, there was nowhere for that extra electricity to go, thus leading to an overheated wiring that increased the risk of fire. The lack of ground, the knob and tube wiring is not compatible with modern household power usage demands. It is important that the modest residential power have less power usage as it can put a great deal of stress on an old knob and tube wiring scheme.

Rewiring your whole house to protect yourself of knob and tube wiring is a long term investment that will depend on the size of your home and the cost of it. That’s why, it is highly recommended to update the wiring in segments by beginning with the kitchen and later moving throughout the house when possible.

It is always worth to take some time and inspect your property to find out. If you think that your home may feature knob and tube wiring, Rushforth Electric and Heating (1976) Limited will help you determine the safety of your wiring and provide rewiring services if necessary.

Everything You Should Know About Knob and Tube Wiring

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