What do I need to know about insuring a home that has knob and tube wiring?

Homes that were built before 1950 have a specific type of electrical wiring known as "knob and tube'. Modern wiring is usually run through plastic or PVC tubes, while "knob and tube' wiring consists of porcelain insulating tubes that contain wires. Porcelain knobs are used to carry the wire around corners while the porcelain tubes pass through rafters, walls and beams.

Because some insurance companies aren't pleased about taking on a house they perceive as risky, homeowners with this older wiring might find it difficult to purchase a policy. In order to show that the coating on the wiring is in adequate condition, many insurance companies require an inspection.

If the inspection goes well, they are probably going to write you a policy. If the inspectors saw something improper about your wiring, the insurer might ask for you to hire a qualified electrician for necessary repairs and evaluation.

Homeowners should make sure that they don't have too much electrical equipment plugged in, such as stereos, computer, etc... because older houses often have a lower capacity in their wiring systems.

A fire might result from an electrical overload easily. According to Mark W. Early, assistant vice president and chief electrical engineer for the National Fire Protection Association, knob and tube wiring may be safe to use but it should be replaced when wire insulation is brittle or cracked. Proper maintenance with all electrical system components is crucial, according to Early.

Phil Supple, spokesperson for State Farm Insurance Co., considers knob and tube wiring a dangerous concept. "Because knob and tube was generally used so long ago, we are concerned about the deterioration of the electrical system as a whole,' explains Supple.

Another issue that comes up for State Farm is the lack of a ground wire with this style of wiring. Keep in mind that knob and tube consists of two wires: a "neutral' one that completes the circuit and a "hot' one that carries electricity to its destination. Chances of creating a fire hazard are reduced with modern wiring through the use of grounding wire.

Before State Farm will insure an older home, they require a certificate of inspection from a qualified electrician. If the inspection goes well, then State Farm might write you the policy.

If the wiring is old an in shoddy shape, the lack of a ground wire can be a problem agrees Mike Johnston, education coordinator for codes and standards for the International Association of Electrical Standards.

Finding an insurance company willing to insure homes with "knob and tube' wiring won't be easy.