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​Knob and Tube Wiring – An Early Wiring System

Knob and tube wiring was a common wiring system installed in Orange County area homes between 1880 and 1935. Wires were wound around ceramic knobs and drawn through ceramic tubes. If your home was built in this period, feel free to call our in-office electrician for a free consultation on whether your home might have knob and tube writing.

You can also check in the attic or crawl spaces for ceramic knobs and tubes like those pictured here.

It’s a virtual certainty that a knob and tube electrical wiring system in the Orange County area is no longer safe today. We recommend a house rewire if you have this type of system. In addition to providing protection for your family from fire and electric shocks, rewiring can lower your insurance rates and represents a good investment should you ever wish to sell your house. Rewiring could also provide your home with more adequate power for today’s appliances and protect your electronics from long-term damage due to knob and tube’s lack of grounding

Is Knob and Tube Safe?

Knob and tube wiring can pose a fire hazard. In addition, since knob and tube is not a grounded system, malfunctions in appliances or in the electrical system can pose electric shock hazards. Lack of grounding can also, over time, cause continuous low level damage to electronics in your home.

Many insurance companies do not offer fire insurance for houses with knob and tube wiring. Also, many mortgage companies will not give loans on such homes.

If you would like help in determining if your older house has knob and tube wiring, give us a call.

Insufficient Power Problems with Knob and Tube Wiring

Knob and tube was in use long before homes had entertainment systems, computers, and large refrigerators. Knob and tube wiring systems were simply not designed for today’s electrical loads and may not provide sufficient power. As a result, with knob and tube, you may be blowing fuses or flipping circuit breakers.

Some homeowners attempt to deal with insufficient power by taking the dangerous step of over-sizing fuses or circuit breakers. This will allow greater electrical flow, but if more electricity flows than the system was designed to handle, wires and connections can overheat and catch fire.

Insulation Hazards in Homes with Knob and Tube

Fire is a hazard if building insulation is blown over knob and tube wiring or insulation batting is placed up against it. Most homes with knob and tube wiring that have had insulation installed in their attics have this unsafe situation.

Lack of Grounding

Knob and tube wiring systems are not grounded In addition to the shock hazard posed by ungrounded systems, such systems can build up electrical charges that can cause continual low-level damage to electronics. This damage can shorten the lives of computers, entertainment systems, refrigerators, microwaves – any device which includes electronic components.

An even greater hazard of lack of grounding is the potential for electric shocks. If an appliance or the electrical system malfunctions, it’s possible to receive a shock which could cause injury or even death.

Can a Knob and Tube Wired House Be Insured or Sold?

Probably, but you may have to look around for an insurer or mortgage lender. Some insurers will not insure a knob and tube house without an inspection by a licensed electrician. Many will not insure or re-insure such a house at all. It may also be difficult to obtain a mortgage on a knob and tube house. That may limit the potential for re-sale.

What Steps Should Be Taken If My House Has Knob and Tube?

If your home has knob and tube, it should be inspected by a qualified electrician to determine its safety. Give us a call to schedule a Free Home Safety Inspection or a free consultation.

Knob & Tube Wiring