If you have knob and tube wiring in your home then you know you are dealing with an older wiring system and you’re going to need to consider whether it is safe or not. You should note that there is nothing inherently unsafe about this type of wiring system as an installation. However, as it ages this type of system is likely to be an increased fire risk.
Understanding Knob And Tube Wiring
Knob and tube wiring originated in the early 20th century. The wires were run overhead with porcelain insulators and attached to walls with ceramic knobs. These also served as connection points, two or more wires could be wrapped around a knob to connect them and continue the circuit.
Wires were run inside metal tubes to help efficiently cool them and the knobs and tubes would also ensure there was a gap between the wires and the walls of your home, effectively preventing you from getting an electric shock. This was before the addition of an earth circuit.
The joints to appliances were protected by cloth insulating sleeving, this was originally asphalt-saturated cotton but rubber became a popular choice.
If you have knob and tube wiring in your home you need to have a qualified electrician Sydney take a look at it. Although initially considered safe, this type of system is no longer approved for use and it is highly likely that you should replace it.
The Dangers Of Knob And Tube Wiring
Wires are passed through metal tubing without any earth. Over time wires degrade, as does the metal tubing. In addition, the tubing can be damaged. All of this can combine to allow the tubing to carry an electrical current, potentially shocking you if you touch it.
Alongside this, the damage can cause short circuits. This can cause issues with appliances. More concerning, it can cause a fire to start as these circuits are not protected by modern, fast-acting, circuit breakers.
Knob and tube wiring has no earth, automatically giving you a higher risk of an electrical shock.
It’s also worth noting that rubber was often the insulation used in knob and tube wiring. Over time the rubber will have deteriorated, especially if there is excessive heat, such as in the attic. Without the insulation, the bare wires are exposed and increase the risk of shocks, short circuits and fires.
Equally, the power draw of modern appliances is significantly more than it was when the knob and tube wiring was installed. In other words, the circuits are not capable of carrying the current without overheating and potentially causing issues.
Although a rewire is expensive, if your property has knob and tube wiring the safest approach is to have it all removed and replaced with modern wiring, including a modern switchboard and circuit breakers. It may even be considered essential for insurance purposes.
Although this can feel like an expensive option, in reality, it is a little more expensive than extensively checking your knob and tube system, which you would need to do if you were to continue using it. You’ll also get peace of mind with a new system.