Ground Fault Receptacles

 

Effective July 28, 2006 UL943, the Underwriters Laboratories Standard for Ground Fault Circuit Interrupters, will require that GFCI Receptacles meet new requirements when a device reaches its “end of life” (EOL).  The following is the exact wording from UL943:

 

5.15.5 When the internal test function is performed, a ground-fault circuit-interrupter receptacle that reached its end of life shall comply with either (a) or (b):

 

a) Indicate by visual means, audible means, or both, that the device must be replaced.

 

b) Render itself incapable of delivering power.

 

End of life infers that when the device is manually tested, (using the “test & reset” buttons) the GFCI functionality feature is no longer available.  UL requires a visual or audible indication to inform the user that replacement of the unit is needed.  An alternative to informing the user to replace the unit would be to permanently shut off power to the receptacle outlets and down stream loads.

 

Hubbell chose to comply with this new requirement by informing the user to replace the device.  A visual indication that the GFCI receptacle has reached its “end of life” is provided in the form of a blinking red LED.

 

Hubbell chose this method of compliance to the new UL943 requirements for the following reasons:

• Shutting down the power to a receptacle without warning or indication could cause confusion as to where the problem existed.  The user would be uncertain if they had a circuit breaker problem, equipment failure or if the receptacle had failed.  The blinking red LED is a certain indication of the GFCI receptacle failure.

 

• The user would immediately be forced to find alternative sources of power.  It was anticipated that some of these “work-arounds” for alternative power sources would create unsafe conditions (cords under carpet, overloaded power strips, extension cord trip hazards).

 

• Loss of GFCI functionality does not mean that a ground fault is present or a hazardous condition exists.  A GFCI receptacle that has lost its functionality is as safe as a standard receptacle.  It still has the standard grounding feature that a standard receptacle has to protect the user in the event of a fault condition.

 

Some of our competitors have decided to use UL option “b” in order to comply and permanently shut down power to the GFCI loads.  This is a legitimate choice but it should be understood how this is accomplished.  The trip mechanism is not being tested on select competitive GFCI devices.  A test does not occur when the “TEST” button is depressed.  The device is manually tripped when the “TEST” button is depressed.  No electronics or mechanisms are tested when the “TEST” button is depressed.  The electronics are only exercised to allow the device to be reset when the “RESET” button is depressed.  It is important to understand that during this test sequence at no time are the electronics and solenoid actuated to trip the GFCI as in the Hubbell product.  The supervisory circuit test as defined by UL is not performed.

 

Other competition comply with UL option “b” by monitoring a limited selection of electronic components and if failure of a selected component is sensed the device trips.  The flaw in this method is that all of the failure modes are not detected because of the limitation in component selection.  Hubbell does not believe that these are true tests of the products ability to perform as needed in real life.

 

Why choose Hubbell over the competition:

1. A true test of the product is performed to real life conditions.  Any system failure will result in EOL indication.
2. Hubbell complies with UL943 Supervisory Circuit requirements rather than special exceptions.
3. Emphasis is placed on robustness, system integrity and longevity of the product.
4. There is absolute certainty of indication in the event that the product fails.  A red LED blinks instead of the confusion of where a power failure occurred.
5. A choice is provided to avoid unsafe work-arounds.

 

It should be noted that effective July 28, 2006, UL943, clause 5.14.5 goes into effect that all GFCI manufactures comply to equally.  No power is allowed to the outlet face of the GFCI receptacle in the event that the GFCI is “Line to Load” miswired.  This clause is unrelated to the “End of Life” issue.

 

As technology advances, Hubbell will lead the way by introducing new products with enhanced features that answer our customer’s needs.  Hubbell is presently active with the CPSC, UL, CSA and NEMA in developing the next generation of safety standards.

 

Mike Holt’s Comment: I prefer that when the GFCI has reached it’s end of life and it no longer provides GFCI protection that the device be rendered inoperative, rather than having a flashing light, that the customer has no clue what it means. In addition, I understand that the 2008 edition of UL 943 is going to require option ‘b’ only.