What are the Concerns About Knob & Tube Wiring?

The charm of an early 1900s house is sometimes undeniable—and irresistible. Whether you are living in one now or hope to buy one soon, you may have one big concern on your mind: the home still has knob and tube wiring.

Here we discuss the pros and cons of knob and tube wiring.

But first, what is knob and tube wiring, or K&B?

Knob and tube wiring is an early method of electrical wiring commonly used in North America from around 1880 until the 1930s. Made from single-insulated copper conductors within wall and ceiling cavities, it is passed through joist and stud drill-holes wrapped in protective porcelain insulating tubes. For support, these tubes are nailed down with porcelain knob insulators.

While masterful for its era, today, some consider this form for carrying electricity dangerous for homeowners. Others consider it masterful still.

The Pros of Knob & Tube Wiring

According to Asmint Cruz, CEO of AC Electric, HGTV may have created undue panic when it comes to K&T. “I’ve been working on homes with knob and tube wiring for over 15 years.

“What I have noticed is that none of the connections which were original have come loose and/or started a fire,” he writes. “The installations have remained free from problems from the day they were installed. K&T installations are a far superior installation than today’s common use of NM cable.”

The Cons of Knob & Tube Wiring

However, others feel it may be more serious. Realtor Richard Silver notes, “It was not conceived that K&T wiring would be used to run washing machines, televisions and other modern day gadgets and appliances. As this type of wiring does not bear much of a load, there is a possibility that it could be high risk and lead to fire hazards.”

As Cruz alluded, amateur repairs performed on knob and tube wiring may result in poor quality and even negligent work.

Due to these dangers, insurance companies sometimes refuse to insure homes with this type of wiring. If they do cover it, it comes at a hefty cost.

Should I replace knob & tube wiring?

For safety reasons, it may be recommended that knob and tube wiring be replaced with up-to-code electrical wiring. On the other hand, knob and tube may actually be more sound—if no one has tampered with it.

To determine if you should replace your current wiring, have a professional evaluate your home to see if there are any visible signs of potential danger or hazards. If no signs exist, knob and tube may cover your needs with some minor updates.


To learn more about the K&N in your home, contact AC Electric today.