Knob and tube wiring: what homeowners should know

Have you ever seen some strange looking wires wound around ceramic cylinders in your basement?

You may have knob and tube wiring, also known as K&T wiring. K&T wiring was a primary method for North American home electrical systems from the 1880s to the 1940s, when it started phasing out for more modern and safer methods.

K&T electrical systems use copper wiring (often covered with fabric or rubber coverings and sometimes insulated with hazardous materials like asbestos) that runs through the framework of a home via ceramic “knobs” and “tubes”. The knobs hold the wiring in place while the tubes allow wires to pass through wooden structures like joists, walls, and beams.

Many insurance companies and municipalities may require that knob and tube wiring be decommissioned and replaced with modern, code compliant solutions. However, the National Electrical Code (NEC) doesn’t necessarily require its removal if it remains in good condition.

So, the question many homeowners face when they find K&T wiring in their homes is: “Is it safe?”

The question of safety isn’t necessarily an easy yes or no. Knob and tube isn’t inherently dangerous, but factors like age, modifications, insulation conditions, and household electrical usage can make it a real risk for fire or shock hazards.

• Age: K&T wiring is prone to safety concerns, in part, due to how long it’s been around. Insulation or wiring coverings are often brittle and damaged due to age. Live wiring could have been covered by home insulation over time, creating a stronger risk for a house fire.
• Modifications: Because K&T wiring has been around for a long time, and because the wiring is more accessible than in modern methods, modifications made by previous homeowners or unqualified technicians are common. These modifications are often unsafe and create poor connections in the wiring.
• Insulation Conditions: K&T wiring doesn’t have the plastic insulation utilized in modern wiring. The fabric and rubber coverings used in K&T wiring are prone to breaking down over time and can eventually lead to wires becoming exposed. This increases the risks of fire, electrical shock, and further damages.
• Household Electrical Usage: K&T electrical systems weren’t designed to handle the electrical loads of modern household appliances. With technology, gadgets, and appliances making their way into our everyday lives, K&T wiring can’t keep up with the electrical load of a 21^st century home, and the circuits begin to fail. Wiring can become damaged, and breakers can trip repeatedly due to this incompatibility.

So, what should you do if you believe you have found knob and tube wiring in your home?

Call a licensed and qualified electrician to take a look and determine if the K&T wiring is still in use. Many homes may have the remnants of knob and tube electrical systems even after they’ve been decommissioned and replaced with modern wiring. If this is the case, often, no further action is needed. However, if the electrician finds that the wiring system is still in use, they can help guide you through potential solutions.

Home wiring issues can be intimidating for any homeowner. Our team at Electrical and Data Service Company wants you to rest easy knowing that our experts can help you by inspecting your home wiring and identifying the best plan for your needs should remediation or replacement be required. We will work with you every step of the way and make the process as simple and easy as possible, giving you peace of mind and reassurance.