"A safety revolution is underway in the electrical wiring of buildings,” writes Earl Roberts in his book Overcurrents and Undercurrents.1 He is writing about the use of electronics in circuit protection and specifically in the ground-fault circuit interrupter (GFCI). Just as electronics have enhanced the world of consumer appliances and communication, the use of electronics in the GFCI has resulted in a significant improvement in the safety of electrical systems.
Proven GFCI Safety Record
Notice Roberts’ use of the word "safety” as being under revolution. The GFCI indeed revolutionized the safety of electrical systems. Its purpose is to protect people from electrical shock or electrocution. It first appeared in the 1968 edition of the National Electrical Code (NEC) in Section 680-4 to protect underwater lighting of swimming pools. The successful use of GFCIs in providing electrical shock protection has resulted in continued expansion of GFCI requirements in successive editions of the NEC. Its application under the NEC has grown such that in the 1999 edition it is required in specified locations in kitchens, bathrooms, garages, unfinished basements, pools, fountains, rooftop receptacles, construction sites and elsewhere. Confirmation of the GFCI’s contribution to safety is seen in the reduction in electrocutions since the GFCI’s introduction. Whereas in 1975 there were 650 reported deaths related to consumer products, in 1996, there were 190—less than one-third of those in 1975. This information comes from the Consumer Product Safety Commission. Many of the lives saved can be attributed to GFCI protection.
Useful Service Life
As with any electronic device, the GFCI will eventually reach the end of useful service. Think about a TV set that has finally reached the end of its useful performance. The picture or sound that had once been clear and enjoyable is no longer so. In fact, the unit may simply be "dead.” We have to replace it if we wish to continue receiving our programs. The end of life for other electronic devices, however, may not be immediately evident to the consumer. For safety related devices, it is therefore essential that, if test features are integral in the design, the consumer has the discipline to use those features.
Although GFCIs have proven to be dependable products with a long service life, they must be replaced if their useful service life has expired. They are providing valuable protection that should be maintained. Replacement is also required to maintain compliance with the NEC. To help know when to replace them, manufacturers provide a test button feature available to every user. The instructions provided with or marked on every GFCI unit tell the consumer to test the unit monthly. The test-button feature and standardized instructions are an industry wide requirement of UL 943, Underwriters Laboratories Standard for Safety for Ground-Fault Circuit Interrupters.
The push-button test is simple for anyone to perform: push a button and confirm that the unit trips. Each GFCI has a test button that can be pressed to give a visual indication that the protective electronics in the GFCI are operating. The button is marked "TEST”on both circuit breaker and receptacle type GFCI’s. When this test button is pressed either the circuit breaker handle will move to the trip position or the "RESET” button on the receptacle type GFCI will pop out. There will also be an accompanying audible click. If the GFCI is working correctly, all power to downstream outlets will be disconnected when the test button is pushed. Power will be restored when the "RESET” button is pressed on the receptacle GFCI or the circuit breaker handle is reset.
If there is no tripping indication, the unit is no longer functioning as intended and must be replaced. The GFCI will still permit electrical current to flow if it is kept in service, but the electronic circuitry will no longer provide protection. The person doing the testing must respond to the test. A GFCI is not like the TV that is no longer useful when it stops functioning. The GFCI is designed to continue to permit current to flow, as if it were a standard receptacle or circuit breaker, to supply power until the device can be replaced.
Field Status Questioned
The November/December 1999 IAEI News carried an article titled, "Are All Those GFCIs Out There Working?” The survey cited in the article draws attention to the possibility that a percentage of GFCIs are no longer operational and then concludes that a feature developed by the company employing the author be adopted for all GFCIs as a solution. The issue of potentially non-operational units deserves careful investigation.
The survey information presented in the article was first communicated to manufacturers of GFCIs in August 1999. NEMA member companies have begun an evaluation of the facts. NEMA manufacturers have no information that supports the level of non-functionality indicated by the information presented in the article. Several manufacturers have reviewed their records and conducted informal surveys that seem to contradict the information contained in the article.
As we review the information in the article, we find that the survey failed to take into consideration the method used to test the GFCI, the age of the home, the age of the GFCI and the cause and mode of GFCI non-functionality. A number of items from this early information need to be better understood before the information can be used constructively by GFCI manufacturers or by standards developers for the purpose of revising product standards.
In order to establish the facts scientifically, NEMA members are initiating a study of the state of GFCI units in the field to be completed in 2000. To accomplish the study, training is being provided to those performing the checks, a specific test protocol has been established, and non-operational units will be collected and examined for cause. Age and condition of any non-operational units will be recorded. UL has been supportive of the NEMA study and UL will coordinate documentation of information collected. The intent is to learn if units are non-operational and, if so, to determine the cause and percentage of non-operational units.
Product and standard improvements over the years have already dealt with many potential causes of GFCI failure such as lightning, environmental conditions and incorrect installation. Products produced before these improvements were made may expire earlier than newer products. One value of a study such as the one NEMA is initiating is that the cause of non-operation can be learned and addressed. Date of manufacture will also be learned for any products that have expired. Until the causes of non-operation are known and the level of non-operation has been verified, improvements cannot be identified, if any are needed.
It should be clarified that GFCI test functions are performing as intended, to the best knowledge of manufacturers. The test button feature provided correctly indicates products that have expired and must be replaced. It may be found that residents are not checking units and replacing those that are non-operational. Although manufacturers have taken steps to improve reliability and surely will continue to do so, residents must do their part in checking their units and replacing any that have expired. Some units have been in use for over 25 years.
The solid protection brought to the use of electricity by the GFCI is a matter of record. It is a record that endorses the early work of Professor Charles Dalziel who helped define what protection is and introduced the first GFCIs. It also endorses the advent of electronics that permits the protection to be widely available. The industry is committed to knowing the status of GFCI products in the field. To retain the solid protection that is already available, residents must include periodic checks of their GFCIs just as they do for fire alarms to be sure that safety equipment is operating properly.
1Earl W. Roberts, Overcurrents and Undercurrents, Mystic Publications, Mystic, CT, 1996.