Knob & Tube Inspection
What Is Knob & Tube (K&T)?
The main safety feature of any electrical system is the insulation surrounding the wiring. This was present in even the earliest Knob and Tube wiring systems. When someone refers to knob and tube wiring, they are really describing an insulation system.
The Knobs were porcelain spacers nailed into the wood used to keep the cloth-covered wires from touching the wood.
The Tubes were porcelain cylinders used to line bore holes through the wood. The cloth-covered wire was threaded through the tubes to insulate the wire from the wood.
When doing an inspection, we identify knob and tube wiring by the cloth covering the wire and not the literal knobs and tubes. We do this because we cannot see into the hardware inside the walls. We look for old cloth wires that require the Knob and Tube hardware.
Who Needs a K&T Inspection?
Current homeowners: The wire jacket is a safety feature. Inspections work best before failure. We generally advise homes to have yearly safety inspections. Homeowners with GEN3 Electric & HVAC maintenance plans have this type of inspection included.
New home purchasers: When buying a new home, it is advisable to have an electrical inspection. Home inspectors do not inspect electrical systems — they only report on surface issues and include exemptions in the fine print. Homes built before the 1960s are likely to have outdated wiring. That means the insulating materials could be 60+ years old. Inspections and replacement should occur before failure.
Home sellers: When selling a home, many homeowners want to address as many issues as possible before going on the market. This is a good time to fix problems. Surprises during the inspection period can be unpleasant and can cause a sale to fall through.
Why Do You Need a Knob & Tube Professional?
There are many ways old homes hide K&T. A home’s history can have honestly concealed this old wiring. Handymen and well-intentioned homeowners may have hidden outdated wires in their efforts to improve their homes.
Three-prong outlets were added to older wire systems as a common practice. This is no longer allowed and can be dangerous, as Knob and Tube systems are not grounded.
An electrician may have needed to extend a wire during a renovation. Extensions can hide the presence of knob and tube wiring.
Other times, contractors apply tricks on purpose to fool home inspectors and their testers. This can be a safety issue for the home and its occupants. A “bootleg ground” is one such trick — it fools an electrical tester into reading the system as a 3-wire system rather than a Knob and Tube system.
Conclusion
While inspections of knob and tube wiring may seem daunting, they are relatively straightforward projects that can pay for themselves in home value, safety, and efficiency. A professional technician can assess the condition of your knob and tube wiring system quickly, often within a matter of hours. With this knowledge, you’ll be able to make an informed decision about repairs or replacements to avoid potential dangers. It’s never too late to get an inspection, so don’t delay — contact GEN3 Electric & HVAC today at (267) 435-3507">(267) 435-3507 for an old wire inspection. Remember, an ounce of prevention goes a long way toward preventing dangerous accidents throughout your home.