Since a third of American homes were built more than 50 years ago, home buyers and folks living in an older home should be aware of how wiring changed during the last century. During the 20th century as new appliances appeared on the scene  electricity evolved from a luxury to a mainstay, causing residential electrical wiring changes.  More appliances also led to safety improvements and an increased number of room outlets leaving older home wiring to play catch-up.  Although most older home electrical systems have been upgraded over the years, safety shortcomings may still exist.

An estimated average of 32,000 home fires are caused by household wiring and lighting each year resulting in 950 injuries, 220 deaths and nearly $674 million in property damage according to the National Fire Protection Association.  Residential electrical systems are seldom inspected after they are installed and tend to be destroyed in house fire, so needless to say, homeowners should not assume all is well simply because fuses aren’t blowing, circuit breakers tripping or they’re not receiving shocks or smelling burnt plastic.

If on the other hand, anytime you receive a shock from an electrical appliance, outlet, or wall switch in your home, it’s a warning that you should talk with a qualified electrician.  If a fuse blows or a circuit breaker trips right after you replace or reset it, you have trouble somewhere.  Also, flickering or dimming lights could mean loose connections, overloaded circuits, improper wiring, or arcing and sparking inside walls.

Another issue associated with older home wiring systems is the number of receptacles in each room.  Today’s electrical code requires outlets be placed every 12 feet of running wall space, about one per wall in the averaage 10-by-12-foot room.  Houses built before 1956 were required to have outlets placed every 20 feet, while homes built before 1935 weren’t required to have wall outlets at all!  Another hazard is one of using extension cords as a permanent solution.  These are meant for temporary use only.

Proper grounding, meanwhile, prevents painful or even deadly electrical shocks when electricity flows through an improper path.  Newer homes are wired with cables that include a ground wire.  The ground wire allows for use of three-pronged receptacles needed to power certain appliances, particularly ones with metal shells, such as refrigerators and washing machines.

Many wiring systems installed in the 1950’s and earlier used non-metallic wiring, which lacked a ground wire.  Homes from this era boast only two-pronged outlets, unsuitable for many modern conveniences.  Simply replacing two-pronged receptacles with three-pronged receptacles violates the National Electrical Safety Code if no ground path exists.

In some cases, older homes may feature newer wiring systems.  But the era when the wiring was upgraded impacts electrical limitations.  So if you are in the market for buying a home whether it be a new one or an older one, be sure you have someone certified in electrical work inspect the system to be safe.