Somewhere Charles Dalziel is smiling.
Today his remarkable 1961 invention— the ground fault circuit interrupter (GFCI)—is found in nearly every American home, apartment and place of business. The GFCI is credited for saving scores of people from electrocution injury or death.
The GFCI has undergone a series of enhancements since its first appearance in circuit breakers in 1968 and four years later in plug-in receptacles. Just last year, a revision to the UL 943 standard mandated one of the most significant upgrades in GFCI history: A new self-test (auto-monitoring) feature is now built into all GFCI receptacles and GFCI circuit breakers manufactured after June 29, 2015.
Taken for Granted
The new self-test feature is the industry’s recognition that many, if not most, users take the GFCI’s performance for granted. They shouldn’t. For example, an electrical surge can damage the ground fault sensors, leaving users vulnerable to the risk of electrocution. Manual monthly testing goes a long way to minimizing that risk. But expecting users to test with that frequency overlooks human nature.
Bill Grande, senior director for residential products at Leviton, a leading maker of electrical supplies, likes to illustrate this issue with a story. Grande frequently leads training sessions on electrical products. “I often ask for a show of hands to the question, ‘How many of you have GFCI receptacles at home?’ Generally, all hands go up. Then I ask, ‘How many of you have tested them in the past month?’ I’m lucky to see a single hand go up,” reports Grande.
New self-test receptacles proactively test themselves for the ability to detect and respond to a ground fault. If the test reveals that the unit no longer offers protection, the receptacle emits a visual or audible signal and will automatically trip itself if it is able to and will not allow the user to reset it if the receptacle cannot provide protection. It’s an extra layer of safety that GFCI receptacles have never offered before.
So, what about circuit breakers?
The GFCI Circuit Breaker Exception
The same self-testing feature is similarly required for circuit breakers, but with exceptions. The new UL standard does not require circuit breakers to respond to all of the same “end of life” scenarios that it requires for receptacles. Circuit breakers are not required to perform any actions if the solenoid or silicon-controlled rectifier (SCR) fail. This could create a potentially hazardous situation, because these components are critical parts of the tripping mechanism. A lack of indication could lead users to believe that they are protected against ground faults when, in actuality, they may not be. The distinction between receptacle and circuit breaker technology is an important one. Trade professionals and users understandably may think GFCI-equipped circuit breakers and receptacles respond identically to a positive self-test result. They do not.
“Should there be consistency between circuit breakers and receptacles?” asks Grande. “Absolutely. The GFCI standards should be consistent. It would be helpful to installers and consumers if both products had similar requirements.”
No one disputes the layer of extra safety that the new self-testing capability presents in circuit breakers and receptacles. But for now, only self-test receptacles offer users an even higher level of safety from ground fault accidents.
About Leviton: Leviton is the smart choice, providing the most comprehensive range of solutions to meet the needs of today’s residential, commercial and industrial buildings. Leveraging more than a century of experience, Leviton helps customers create sustainable, intelligent environments through its electrical wiring devices, network and data center connectivity solutions and lighting energy management systems. From switches and receptacles to daylight harvesting controls, networking systems and equipment for charging electric vehicles, Leviton solutions help customers achieve savings in energy, time and cost, all while enhancing safety. For more information, visit www.leviton.com, http://www.facebook.com/leviton, http://twitter.com/leviton or http://www.youtube.com/Levitonmfg