Dangers of Knob and Tube Wiring

Reasons You Need to Replace Knob and Tube Wiring

Living in a home that is many decades old? If so, you probably have things you both like and dislike about it. A home with a duration of history behind it can be intriguing, especially if it has been in the family for many generations. However, keeping an old home functioning properly can certainly take much effort. If you have a list of updates and renovations you need to make to your older home, you should add “replacing knob and tube wiring” to the TOP of the list.

What is Knob and Tube Wiring?

Invented in the late 19^th century, and phased out in the mid-20^th, knob and tube wiring was one of the first methods for outfitting a private residence with electricity. It consisted of suspending non insulated wires inside the walls using porcelain knobs. These knobs ensured that the wires did make contact with the walls, which could cause a fire. In those areas where the wire had to pass through a wall, it would be surrounded by a tube with a type of cloth sleeve in it. That is where they get the name “knob and tube” wiring.

This was quite the innovative technology in the late 1800’s, but by the mid-1900’s the growing installation of insulated wiring caused knob and tube wiring to be phased out. However, there are still plenty of older homes in use today that use knob and tube wiring.

Dangers of Knob and Tube Wiring

Knob and tube wiring is likely over a century old and still unsafe. This non insulated wiring is not something to ever use, as there are other options. There are very high odds of something accidentally contacting the wire, causing a short and possibly sparking a fire. The wires used in this system are not rated to handle the standard 21^st century, increasing the odds of dangerous situations. In the beginning of the 20^th century, the average home used much less power than what we do today. That extra load takes its toll over time; putting that much voltage through an old wire for which it was never designed will cause serious problems.

Overview of the dangers:

• No ground: Only a hot and neutral wire are provided. Watch out: A knob and tube electrical circuit has no electrical ground path.

• Wire insulation: The individual electrical wires are wrapped in a rubberized cloth. That was fine when the wires remained suspended in air and had not been chewed by a squirrel or surrounded with insulation

• Knob and tube wiring connections or splices were made outside of electrical junction boxes. In normal practice knob and tube wiring splices are soldered and also taped.

• No electrical grounding conductor is provided. Grounding conductors reduce the chance of electrical fire and damage to sensitive equipment. The circuit is less safe than a modern grounded electrical circuit and appliances and devices that use a grounded plug should not be connected on an un-grounded circuit.

• The knob and tube wiring may have become damaged by age, exposure to leaks, or to chewing rodents. In attics, for example, we often see that this wiring has been damaged by having been stepped-on or by chewing rodents.

Replacing Knob and Tube Wiring

Knob and tube wiring can take quite a lot of time to replace and can require a large investment if the majority of your home uses it. However, the cost to replace the system is very well worth it compared to the damage that old knob and tube wiring can cause. If you know that part of your home uses knob and tube wiring, don’t wait to have it replaced.