old wiring systems in homes?

what should an inspector do when they encounter old-style wiring systems like fabric-coated wire or knob and tube wiring. Should they recommend that it be evaluated by an electrician? Is there anything that an inspector can do to confirm that it’s safe? Are either of these systems so bad that they should be replaced no matter what?


And a little education (explanation of the concern) wouldn’t hurt.


The electrical wiring systems that power the conveniences of modern life are hidden in walls and in panel boxes in basements. They are out of sight and out of mind. But that does not mean they are not overloaded and under severe stress.

**As homes in the United States age currently half of all homes are at least 50 years old their wiring systems may not be keeping up with the ever-increasing demands placed on them. As their quality and safety deteriorate over time, potential hazards posed by aging residential wiring systems can be unseen or just casually neglected by homeowners or renters. Older wiring systems, especially cloth covered wiring, most likely will not have a grounding conductor (a third wire to conduct excess flow). Most of today’s electrical appliances are designed to operate with a three-wire system and should not be used in any fashion contrary to their designed manner. **

According to the National Science and Technology Council’s Wire System Safety Inter agency Working Group report issued in 2000, the aging of electrical wiring systems is a national safety issue.

Each year in the United States, it is estimated that there are as many as 41,500 fires in homes related to electrical wiring systems, resulting in 1,400 injuries and 350 deaths with damage estimates ranging from $650 million to $1 billion annually. While older homes are at a greater risk, newer ones are not immune from the dangers of poor wiring practices or the environmental stresses placed on wiring systems.

The reality is that this is not a witch-hunt for defective products. Most of the electrical wiring systems that went into homes in the 1960s, '50s and '40s are at or close to the end of their design life.
Recommendation: Licensed electrical engineer to survey the electrical system to determine the working quality of the older system.
**Recommendation: Licensed electrician to upgrade the system **as mandated by current standards and is an important safety feature.


Knob-and-tube wiring was commonly installed from the late 1800s until the late 1950s.

Knob-and-tube wiring is made of two individual wires that run through and are connected to porcelain insulators. The system lacks a ground wire and is associated with fuses rather than circuit breakers. The grounding wire in modern systems reduces the chances for creating a fire hazard. Knob-and-tube wiring also has a lower capacity, so an electrical overload is easy to achieve with today’s appliances. Especially dangerous is that the coating on knob-and-tube wiring deteriorates and flakes off.
**Wire used before about 1930 is especially vulnerable. **
**Because knob-and-tube wiring is readily accessible in attics and basements, homeowners have often made incorrect and dangerous alterations. For these reasons, the National Electric Code (NEC) requires that the wiring be disconnected and removed if there is any insulation around it. **

A number of insurance companies drop fire insurance if there is any such wiring in the house, mainly because of the deterioration of the electrical system as a whole. Check the terms and conditions of your homeowner’s insurance policy to determine if you are covered; your policy may specifically exclude knob-and-tube wiring. Some insurance companies base that decision on the results of an inspection of the specific home.

**If there is insulation surrounding the knob and tube wiring, it must be carefully removed so as not to damage the coating on the wires. This will ventilate the wires to help keep them from heating up. **

**If you want to insulate around the old wiring, the NEC requires that the knob-and-tube wiring be disconnected and replaced with new wiring before insulation. **
Of course, an electrical permit will be required for any rewiring. With the knob-and-tube wiring disconnected, you’ll have lots of choices for insulating the attic.

Recommendation: Licensed electrician to evaluate this wiring and make repairs or replace wiring as necessary.

"Recommendation: Licensed electrical engineer to survey the electrical system to determine the working quality of the older system."

This sounds good on paper but I wonder what the reality is of finding an electrical engineer to survey a residential wiring system and put his name on it, and at what cost. Most electrical engineers here have a $1,500.00 minimum.


Just covering my butt. If the buyer wants to do it–OK. If the buyer doesn’t want to do it–OK.

I really don’t care if the buyer’s grandmother does the survey…or if a survey is done at all. It’s all up to the buyer.