If you are looking at older homes you may run into knob and tube electrical wiring that is still in use from the original installation of the home. Knob and tube wiring was the standard in the U.S. from about 1880 through the early 1950s. I have come across many older homes in Hawaii that still have knob and tube wiring. As you can see from the video, this type of wiring can be quickly identified by the porcelain knobs that wires and porcelain tubes which protect the wires as they pass through wood framing. This type of wiring is not allowed by current electrical codes and you should consider having it replaced by a certified electrician if it is in your home.
Risks of Knob & Tube Wiring:
- Knob and tube wiring does not have a ground wire. This lack of a ground significantly increasing the chance of an electrical fire and damage to appliances and other sensitive equipment in your home.
- Any knob and tube wiring found in your home is old and the wiring insulation was made of much less resistant materials than today's wiring. It is much more likely that the insulation and actual wiring have been damaged over the years.
- The insulation used on this older wiring is not resistant to moisture and is considered a fire hazard. Additionally, many homes have had electrical modifications over the years which may increase the risk from knob and tube wiring.
- Due to the increased fire and electrical damage risk, many insurance companies will not insure a home that still has knob and tube wiring installed.
What to do if your home or home that you wish to buy has knob and tube wiring:
First of all you should have the home's knob and tube electrical system evaluated by a licensed electrician to determine if it is safe and if replacement is required. Based minimum seventy plus year age of these systems, they will likely recommend replacing the system. While replacing knob and tube wiring is expensive, not replacing increases your risk of fire, can complicate real estate transactions, and may prevent you from obtaining home insurance or paying a much higher rate for insurance.
If you have questions about your home consult a licensed electrician or I can recommend one for you.