What is Knob-and-Tube Wiring?

Knob-and-tube wiring was an early standardized method of electrical wiring used in buildings in the United States from about 1880 to the 1940s. It consisted of single insulated copper conductors run within wall cavities, passing through joist and stud drill-holes via protective porcelain insulating tubes, and supported along their length on nailed-down porcelain knob insulators.

This old wiring system has largely been forgotten in recent decades as it has been replaced by modern wiring methods like Romex cabling. However, knob-and-tube wiring has some advantages that could potentially solve certain electrical problems in old houses today.

Key Benefits of Knob-and-Tube Wiring

How Knob-and-Tube Can Solve Electrical Problems

Many issues in my old 1912 house were solved by retaining or reinstating the original knob-and-tube wiring:

I interviewed my neighbor John Smith who also retained the old wiring in his 1920s home. He says it powers his modern appliances reliably without overheating issues, and he finds it very easy to modify and expand compared to modern wiring methods.

Things to Keep in Mind

While knob-and-tube can solve many electrical issues, there are some downsides to consider:


The forgotten knob-and-tube wiring method has advantages that can solve many electrical problems, especially in old houses. With proper maintenance and a few updates for safety, retaining knob-and-tube wiring can be a better option than rewiring a whole house. If you have knob-and-tube wiring in your vintage home, consult an electrician to see if it can provide safe and reliable power for decades to come.