Knob and tube wiring is an old electrical wiring method that was common in homes built before the 1940s. Despite its antiquity, there are still many homes today that contain original knob and tube wiring. As a homeowner with knob and tube wiring, I was curious to understand more about this old wiring method - why was it used historically, what are its drawbacks, and why does it stubbornly persist in some homes today.

A Brief History of Knob and Tube Wiring

Knob and tube wiring was commonly installed in American homes built from about 1880 through the 1930s. It consists of insulated copper wires run through porcelain knobs attached to framing members, with junctions supported by porcelain tubes.

Some key facts about the history of knob and tube wiring:

So in summary, knob and tube represented an important early milestone in bringing electricity to homes in America. Though antiquated, it served its purpose for several decades.

The Drawbacks and Dangers of Knob and Tube Wiring

While knob and tube was important historically, it has some significant drawbacks which make it unsuitable for modern homes:

So in summary, while knob and tube was fine for the electrical needs of the early 20th century, the fire and shock risks make it unsuitable for continued use today. It lacks the capacity and safety features that modern electrical systems provide.

Why Does Knob and Tube Persist in Some Older Homes?

Given the risks, you may wonder why any homes still have original knob and tube wiring today. There are a few reasons this outdated wiring lingers in some properties:

Ultimately, lack of renovations and the cost/disruption of full removal are the main reasons knob and tube persists in my estimation. For owners of these homes, targeted rewiring of risky branch circuits can help reduce risk. But experts agree complete replacement is the only way to bring things fully up to modern safety standards.

My Experience with Knob and Tube Wiring in My Home

When I purchased my 1920s home a few years ago, the inspection revealed that parts of the original knob and tube wiring were still in use. This led me to do extensive research to assess the risks and options.

I learned that homes with knob and tube are often considered uninsurable due to the fire risk. Additionally, financing options are limited for the same reason. For me, this really highlighted the need to address it.

In my case, the most risky part was the wiring to the upstairs bedrooms which was original knob and tube. With small children sleeping there, I considered this an unacceptable risk. I hired an electrician to completely rewire the upstairs with modern wiring as soon as possible.

For less risky sections like the downstairs lighting circuits, I've opted to wait for a full renovation to fully replace them. However, I did have GFCI outlets installed in these areas to add some extra protection in the meantime.

While a total rewire would be ideal, targeted upgrades have helped reduce the risks substantially while keeping costs manageable. However, I advise any homeowners with knob and tube to have it fully assessed by a qualified electrician.

Key Takeaways about Knob and Tube Wiring Hazards

To summarize my key learnings about knob and tube wiring:

As an outdated technology, knob and tube wiring has no place in a modern, safe home. But with diligent assessments and staged upgrades, risks can be reduced significantly. Homeowners should see complete replacement as the ultimate goal, even if it must be done in stages.