Knob and tube wiring technique were one of the first standardized wiring systems. It was used before the 1940s and it used a single conductor usually insulated with a cloth fabric. Different types of porcelain insulators were used to separate the conductor from the wood in homes. Porcelain cylinders were inserted in holes to pass through the cable from the wood, whereas porcelain knobs were used to secure the wires along the wooden walls and to keep the wires from touching the walls.
Knob and tube wiring system were used when the electrical industry was in its early stages of development. It is relatively difficult to inspect because this type of wiring is inside the walls. This wiring system is not grounded. In modern electrical systems, grounding in mandatory because it makes the wiring safer by reducing the risk of shock in the event of a short circuit or device malfunction. Some insurance companies do not cover the houses with this type of wiring due to the risk associated with it. The decision for the replacement knob and tube wiring can be made by considering few factors, such as the proper understanding of how the system works, the current condition of the wires, and the cost of the replacement.
Dangers of Knob and Tube Wiring
Knob and tube wiring is not itself dangerous, instead, problems arise due to rust and prolonged use. The K&T wiring technique is obsolete and its new installations are not allowed. But, replacement of existing knob and tube wiring is not mandatory, but it should be replaced if it has become fragile and run down.
1. Wire Insulation
Old K&T wiring is composed up of single conducting wire, this wire is insulated with cloth fabric, heat is generated when high current passes through the wire. This heat can cause a fire due to the fragile condition of old insulation.
2. Prolonged Use
Wires become stiff when used for a long time. Sometimes contact with water can cause rust in the wire. This stiff and damaged wire can break at any time. Over time, due to wear and tear, insulating tubes can crack, leaving the wire in direct contact of the wood. Porcelain knobs can also break up leaving the wires hanging and creating possible safety risks.
K&T wiring is generally considered safe if it has not been altered or modified. Some of the changes that make this wiring risky are: Badly done connections and joints, the addition of extra outlets, and changes in the structure of the building.
In the past when K&T wiring was installed, energy requirements for the average household were far lesser than they are today. There were only a handful of appliances and that too did not consume a lot of energy. So, the current-carrying capacity of this wiring was less. Supplying a modern home with this type of wiring can cause the wiring to overheat resulting in a fire hazard.
If you are in need of the Replacement of knob and tube wiring Calgary, you should first get a thorough inspection from the certified professional to access whether or not your K&T wiring needs replacing. After that, decide according to professional advice.