- Features | June 11, 2018
Protection Without Exception
Since the 1960s, receptacles and circuit breakers with GFCI technology have become standard in homes to protect occupants from electric shock. Required by the NEC for outlets located in certain wet or damp locations, such as near bathroom sinks, kitchen countertops, bathtubs, and showers, GFCI receptacles monitor variations in the electrical current flowing through the line. In instances where a person accidentally becomes part of an electrical circuit, a GFCI receptacle would immediately trip, preventing electrical current from going through a person on its way to ground. It’s a technology that can save lives.
But did you know that GFCI circuit breakers don’t have to adhere to the same safety standards that govern GFCI receptacles? Until only recently, UL safety standards for GFCI circuit breakers included exceptions which
may allow for unprotected power to remain flowing through a circuit breaker that has reached end of life.
END OF LIFE, DEFINED
GFCI end of life is defined as when a GFCI is incapable of providing ground fault protection and passing its internal test function. UL 943 Self-Test GFCI End of Life standard states that when a self-test GFCI reaches end of life it must either:
- Deny power with inability to reset;
- Give a visual or audible indication; or
- Trip with reset ability, subject to the next test cycle or repeat tripping
When this standard was adopted it assumed that GFCIs, like all consumer products, have a limited life expectancy
and would eventually reach a point where they could no longer provide ground fault protection. As such, UL included a provision for testing and resetting GFCI devices and encouraged users to test their devices monthly. However, even when diligent users did follow through with regular testing, a GFCI device without true power denial features could potentially be reset and continue to provide power without providing ground fault protection. Naturally, the assumption was that if power was available, so was protection.
AN ALARMING TREND
A research study based on information collected by members of the American Society of Home Inspectors (ASHI) revealed that an alarming number of GFCI devices in homes throughout the U.S. were not providing ground fault protection when tested. The field study reviewed data from more than 13,000 building inspections and found that, on average, 15 percent of GFCIs were inoperative when tested. In areas of the country that experience a high volume of lightning, such as central Florida and the great plains, there was an even higher
incidence of failure, with as many as 58 percent of GFCIs not working properly.
These findings were the catalyst that helped propel the industry toward the reset/lockout style GFCI devices use
today, along with heightened UL safety standards for end of life. However, while these safety standards were universally applied to all GFCI receptacles, many GFCI circuit breakers on the market today took advantage of exceptions in the standards that could allow them to be reset and continue to provide power without ground fault protection. These exceptions pertain specifically to silicone-controlled rectifiers (SCR) and solenoids - two components common to all tripping mechanisms in both receptacles and circuit breakers with GFCI technology. Failure of either of these components may allow the circuit breaker to remain energized.
SAFETY WITHOUT EXCEPTIONS
So what does this mean to the end user? If a circuit breaker with GFCI technology reaches end of life and is no longer providing ground fault protection as a result o