UL Standards for GFC1's have changed: only few meet the new standards.
Revisions to the Underwriters Laboratories (UL) 943 Standard for
ground fault circuit interrupters (GFCIs) became effective in
January. The changes were made in response to research that indicated
that a small but significant percent of GFCIs - particularly older
ones - did not continue to work when evaluated in the field several
years after installation.
According to UL, the 943 Standard revisions are:
* A more stringent voltage surge test to ensure the GFCI can handle
a higher surge current.
* A new corrosion test to demonstrate greater
immunity to most conditions.
* An operating test to verify that proper operation of the GFCI
cannot be prevented by manipulation of the controls.
* A reverse line-load miswire test that requires the GFCI to trip
when miswired.
* An abnormal overvoltage test that requires the GFCI not to become
a fire or shock hazard during extreme overvoltage conditions.
* An increased requirement to operate properly after exposure
to conducted radio frequencies.
Designed to meet all UL 943 requirements, the SmartLock GFCI from
Leviton Manufacturing offers a reset lockout feature designed
to prevent the user from resetting the device if it has been miswired
or installed incorrectly, or if ground fault protecting is lost
due to damage or user abuse.
Yaun Company stocks, the SmartLock GFCI from Leviton in White,
Ivory and Brown.