When Electrical Systems Age

by Nick Gromicko and Elise London

A major component of a house is its Electrical System. This includes the service panel, overcurrent devices and any associated wiring and outlets (receptacles and luminaries). These systems wear out just as anything else but there is one additional major concern here. Overcurrent protection, associated wiring and outlets are major safety items.

Most electrical circuits are designed to be operated at only 80 percent of their rating. While operating above this level may not cause the overcurrent device to trip, it may result in long-term degradation of the circuit wiring and overcurrent devices.

Circuit breakers (overcurrent devices) of some specific manufacturers may be subject to unique problems (example: Zinsco and Federal Pacific).  Several recertification and redistributors of circuit breakers indicate that although they do not keep statistics on specific circuit breaker failure rates they did indicate that Zinsco and Federal Pacific breakers did fail their recertification process at a higher rate than other manufacturers.

Cutler Hammer has this statement about the warranty of their two major residential breaker lines. “The CH style branch breakers carry a lifetime warranty.  The BR style branch breakers carry a life of 10 years.”

BR circuit breakers with the 10 year warranty are used for Cutler-Hammer BR, Westinghouse, Challenger, and Bryant load centers.

Circuit breaker can also wear out from repeated overcurrent tripping or malfunction.  Overcurrent is defined as any current in excess of the rated current of equipment or the ampacity of a conductor. This may be the result from overload, short circuit, or ground fault.

Another concern often associated with older electrical systems is the service panel (load center). Many of these older load centers have small enclosures (gutters). Due to the confined space the bend radius of the wiring is less than what we would accept by today’s standards. Over bent wiring causes excessive heat at the bend of the wires. Wiring is often crowded and has many modifications. Double lugging (two or more wires under a screw) of neutrals and hot conductors is often found.

One more issue that is very common in older homes is over-lamping of light fixture. This is the use of light bulbs that exceeds the rating of the fixture. Over time the increased heat causes an unsafe deterioration of the components and wiring of the light fixture.

The NFPA has this statement from the report listed below -

“Although many homes have had their electrical system upgraded or expanded over the years, many also have not.  The electrical wiring within the home may be the most vulnerable to aging, as it is often buried in walls or ceilings, or installed in attics or crawl spaces that are often not used.  In addition, these non-climate controlled areas, like attics and crawl spaces, can be subjected to extreme temperature conditions and changes, as well as dampness and moisture.  All of these factors can contribute to, or even accelerate, the effects of aging.”

NFPA report on aging electrical systems- http://www.nfpa.org/assets/files/pdf/research/resareport.pdf

Electrical systems have built in redundancy and safety measures. As these systems age the safety factor is most likely being reduced and there is an increased chance for an electrical fire and shock.

Buying a home is usually a very large investment for most people. Understanding the major components of the home is essential for protecting that investment.

Hiring knowledgeable and conscientious Realtors and Home Inspectors should be a top priority when looking for a home to purchase.