As a homeowner, you likely know that outdated electrical systems can present safety hazards. But you may not realize that your home could still contain an antiquated wiring method that dates back to the early 20th century: knob-and-tube wiring.

What is Knob-and-Tube Wiring?

Knob-and-tube (K&T) wiring was commonly installed in homes built before 1950. It features insulated wires that are run through open spaces in walls and ceilings, supported by ceramic knobs and tubes.

While K&T wiring was considered top-of-the-line electrical technology in the 1920s, it does not meet modern safety standards. The insulation on K&T wires becomes brittle with age, leading to cracks and exposing the copper wiring. This can cause electrical arcing, sparks, and potential fires.

How to Tell if Your Home Has Knob-and-Tube Wiring

It can be challenging to identify K&T wiring because much of it is hidden behind walls and ceilings. Here are a few signs your home may contain K&T wiring:

K&T wiring is often uncovered during remodeling projects or upgrades to electrical systems. An electrician can definitively determine if your home has K&T during an inspection.

Dangers and Risks of Knob-and-Tube Wiring

There are several notable risks associated with K&T electrical systems:

These risks make K&T wiring a top safety concern in older homes. The Consumer Product Safety Commission even lists it among the "Top Five Hidden Home Hazards."

Upgrading from Knob-and-Tube Wiring

If you discover K&T wiring in your home, the safest option is to replace the entire system with modern wiring that meets the latest electrical code. Upgrading will likely involve:

Full K&T wiring replacement can cost $8,000 to $15,000 for a typical home, though prices vary based on factors like home size and wiring accessibility.

While expensive, this investment can prevent injuries or fire and provide peace of mind. Some insurance companies may offer discounts when K&T is replaced.

As an alternative, some electricians will recommend only upgrading certain risky parts of K&T systems. However, leaving any K&T wires in place still poses some risk.

Protect Your Home and Family with Updated Electrical

While knob-and-tube wiring served homes well decades ago, it has no place in modern electrical systems. I recommend having an electrician inspect your home's wiring if it was built before 1950. Replacing any K&T wiring with modern wiring will provide essential safety for your family. While not a small investment, preventing potential electrical fires or injuries is incredibly valuable.