Article Provided by New Orleans Electrician
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 home owners or renters. According to the National Science and Technology Council’s Wire Systems Safety Interagency Working Group report issued in 2000, the aging of electrical wiring systems is a national safety issue. Most of the electrical wiring systems that went into homes in the 1960’s, 50’s and 40’s are at – or close to – the end of their design life. If these products are showing some kind of deficiency after 50 or 60 years of service, no one in the industry is hinting that there was a design flaw.
We are on the threshold of an emerging problem.
Across the board, the number of causes of fires is going down due to better codes. Houses being built today won’t have to face the same problems as the lion’s share of the estimated 100 million existing homes in the United States. However, the number of electrical wiring fires in older homes, which can be especially vulnerable to aging wiring and overloaded circuits, is not following the same downward trend.
TOP 3 RESIDENTIAL WIRE SAFETY ISSUES
Degradation is just a natural consequence of being in use for a long time. Heat, light and temperature affect insulating materials, while oxidation and films that can cover conductors at connection points affect conductors. Conductors can also get brittle from flexure and the heat generated from light fixtures, especially those that are over-lamped or left on all the time.
In residential installations, overheating is found many times in applications where homeowners exceed the maximum wattage rating for fixtures. It is difficult to know what circuits in residential installations are heavily loaded, resulting in accelerated loss of plasticizer, (which in turn results) in brittle insulation.
The last major change in residential wiring was in 1985 when the required maximum temperature rating of NM cable was increased to 90• C while keeping the ampacity to 60•C. This has worked very well.
Some electricians use a rule of thumb that says 30-year-old wiring should be replaced since it is difficult to predict how badly it may age.
The second issue is there is more electrical load today as people have more appliances and just expect their electrical systems to keep up. Homeowners will do things like add more circuits or outlets, put in larger fuses or add another circuit breaker where there is a blank spot in their panel. In short they will do whatever it takes to get up and running. The load today is more than what those electrical systems were designed to originally handle just a few decades ago.
The Third factor is that homeowners have involved themselves in the wiring systems and have not followed code practices. Upgrades to wiring systems many times are simple extensions to add additional circuits for additions or kitchen upgrades. Many times these may be done by unskilled people leaving installations that did not meet NEC when performed and certainly do not meet today’s NEC. Do-it-yourselfers and less than skilled electricians can create serious code violations to the point where a lot of the work results in an accident waiting to happen.
For example electrical inspectors could make sure a residence conforms to NFPA 73 before being sold to a new owner, enabling older homes to be gradually brought up to a standard that would eliminate the most common and dangerous aging wiring system hazards.