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You know those unusual receptacles in your bathroom with the little buttons
on them? You know..... the ones that occasionally "trip" out, and cause
your hair dryer to quit? Yes, the very same ones that are sometimes
located in your garage - or worse still - outside (!) that cause your
bathroom receptacles and (sometimes) your lights to go out!
(usually during or after a rain storm)........
This file will attempt to explain the hows and whys of the..... |
{sometimes referred to as.. GFI or GFCI}
A Ground fault can be defined as a "fault" to "ground." This occurs when either of the current-carrying conductors on the circuit becomes inadvertently connected to ground. Examples of this are: Insulation failures in the wiring of buildings or damaged appliances, tools, extension cords; misuse of devices; wiring errors, etc. Some people call this condition a "short" to ground. A GFCI unit is supposed to sense when this occurs, and "interrupts" the circuit by turning it off.
The National Electrical Code defines GFCI's as:
"A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds some predetermined value that is less than that required to operate the overcurrent protective device of the supply circuit." (NEC 1996, Art. 100)
These GFCI devices can come in many different forms:
1) As part of a duplex receptacle assembly, or switch and receptacle combination assembly. This is the most common type found today. The receptacle or combination has a test and reset button on its face, (sometimes very tiny, with hard to see letters on them) to enable testing of its internal switching function. The unit can be wired to protect other receptacles and fixtures "downstream" through the device.
2) As part of a plug assembly on the end of a line cord. This method protects only the device or appliance that is connected to the cord. Portable signs, hairdryers, & curling irons are examples of appliances that can utilize this type of GFCI device. There are extension cords also available with a GFCI built-in on the plug. A test and reset button can be found on the plug to facilitate testing of the unit.
3) As part of a molded case circuit breaker for use in a distribution panel box or load center. A "test" switch will be located on the front of the circuit breaker assembly to allow for testing of the unit. These are available in single pole 15, 20, 25, & 30 Amps, and double pole 15, 20, 25, 30, 40, 50, & 60 Amps, depending upon manufacturer. The 50 Amp double pole is a popular size for 240 Volt Hot tub installations.
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Operation of GFCI devices.
The ground fault circuit interrupter was designed for safety reasons. It has a sensing device that monitors the amount of current flowing through the conductors of the circuit. As long as the circuit conductors have equal amounts of current flowing through them, i.e) the amount flowing "out" is the same as what is "returning" the circuit is maintained. When more current flows out, than returns, there is a "fault" or "leakage" of current from the circuit. The GFCI senses the imbalance in the circuit, and "trips" thereby interrupting the current flow, and causing your hair dryer to quit (while you're still quite wet. The resulting trip out to the cold garage, or into the pouring rain to reset the blasted thing causes you to catch cold) |
The [Class "A"] GFCI trip level is very low, only 5mA (5/1000 Amp +-1mA) or less than 1 watt @ 120 Volts. On homes with outside receptacles on your GFCI circuit, a damp day, and a loose fitting gasket on the weatherproof cover can be quite irritating! The GFCI is supposed to protect you, in case of internal failure of an appliance, or if it is dropped into water while still plugged in. "Why," you may ask, "are the outside and garage receptacles connected to my bathroom? Why don't they have their own GFCI's? Why is my home wired this way?"
GFCI's and the National Electrical Code
The National Electrical Code (NFPA-70) is the standard by which almost all homes are wired in the United States. The first mention of GFCI's is found in the 1968 edition. Prior to then, GFCI's were referred to as "an approved fail-safe ground detector device" or "differential type circuit protection" and were only required for use on swimming pool lighting fixtures. In the 1968 Code, the term "Ground Fault Circuit Interrupter" was defined and required on underwater swimming pool lighting fixtures that did not meet minimum safe performance standards. No GFCI protection was required on underwater fixtures that met the requirements.
The first requirements for GFCI protection for your home came in the 1971 edition of the Code: All outdoor receptacles; receptacles located between 10 and 15 feet from the inside wall of a swimming pool; and power for storable pools.
The 1975 edition of the Code required all bathroom receptacles to have GFCI protection for personnel. Garage receptacles were added in the 1978 edition. Because of the expense of purchasing the GFCI devices during this time period, many electricians combined the required outlets in the bathroom, garage, and outside on a single GFCI breaker or receptacle. This can explain why, in some homes, a visit to the garage or outside may be required to reset a tripped GFCI device.
In the 1981 edition, due to incidences of nuisance tripping of GFCI's some modifications of prior requirements were implemented. Outlets in garages that were not readily accessible (such as on the ceiling for an automatic door opener), and those serving appliances occupying a dedicated space (such as a washer or freezer) were removed from the required list. New requirements were added for circuits supplying whirlpool tubs, spas, and hot tubs. Light fixtures installed over tubs were also required to have GFCI protection.
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Existing non-grounded receptacles were permitted to be replaced with GFCI receptacles in the 1984 edition where no other grounding means existed. This recognition by the Code was the first time that a grounding type receptacle (3-prong) was allowed on a non-grounded circuit (2 wire). The Code severely restricted this substitution, however, and required a separate GFCI receptacle at EACH location on the circuit. "Downstream" protection was prohibited. This requirement seemed somewhat ridiculous at the time, and was eventually changed, but not for another 9 years. This practice can have mixed results, at best. Such outlets must be labeled "No Equipment Ground and GFCI Protected." While you are protecting human life from electrical shock hazard, any sensitive equipment plugged into such outlets are at great risk from surges in the power lines. A surge suppressor unit *must* have a good grounding connection to properly protect your equipment, and operate. A non-grounded circuit with grounded outlets installed on it can lead to a false sense of security, with a surge suppressor that is essentially, useless. You should not allow any sensitive electronic equipment to be used on such GFCI protected circuits, as your equipment will be at risk for failure and burnout in the event of a surge. If your non- grounded outlets are properly labeled, this can minimize the risk of accidentally using one for sensitive electronic equipment or computers. |
GFCI protection for bathroom outlets in hotels and motels was first required in the 1984 Code.
Kitchen receptacles were addressed in the 1987 edition of the Code. Any receptacle above a counter-top and within six feet from a sink were required to have this protection. Receptacles that were rendered inaccessible and dedicated for a specific appliance (such as behind the refrigerator) were exempt from the GFCI requirement, even if located within the six-foot radius. This edition also required at least ONE receptacle outlet in the basement of a home to have GFCI protection, and be so identified. If you had a boathouse built after the 1987 edition was adopted, all the receptacles contained therein were required to be GFCI protected.
The 1990 edition added crawl spaces at or below grade to the list of required outlets with GFCI protection. Additionally, the requirements for at least one receptacle in the basement was changed to ALL receptacles in UN-finished basements. To correct some abuses by contractors and inspectors alike, the wording for the kitchen counter receptacles was modified from ABOVE the counter to ALL receptacles within 6 feet of the sink to serve counter-top surfaces (this includes receptacles cut-in BELOW the counter surface, and was not specifically identified as such in the 1987 edition).
In 1993, the Code added wet bar sinks to the ever expanding list of required locations for GFCI's. The requirements are the same as those for the kitchen sink area: All receptacles that serve counter-top areas located within a 6 foot radius. In section 210-7(d) of the 1993 Code, a new paragraph was added concerning replacement receptacles in existing installations:
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"Ground-fault circuit interrupter protected receptacles shall be provided where replacements are made at receptacle outlets that are required to be so protected elsewhere in this Code." |
| This far-reaching requirement goes beyond the usual "grandfather" attitude
of the Code. As receptacle outlets wear out in older homes in the kitchens,
bathrooms, basements, etc. they MUST be replaced with GFCI type, or
provided with GFCI protection. In some circumstances, receptacles that are
worn out, or broken can be blanked off and eliminated if they are not
otherwise required to be present.
As more and more areas in the home were been added to the list of required GFCI protection, there have been many "innovative" methods utilized by electricians to reduce the actual number of GFCI units they actually had to purchase. The Code, for example, required at least two circuits for the kitchen counter areas. Some electricians would wire the whole counter-top area within 6' of the sink (12' total length) on a SINGLE circuit, supplied by only ONE GFCI receptacle. The rest of the counter areas would be supplied by other (non-GFCI) circuits. The other areas of the home that required GFCI protection would be wired through a single GFCI receptacle located in the garage, basement, or a bathroom. This receptacle would feed all of the other required GFCI receptacles downstream (except for the kitchen counter) with a total of two GFCI's installed in the home. Another reason for that trip out in the cold to reset a tripped GFCI unit while doing your bathroom chores The 1996 edition of the Code continued the addition of new areas and requirements to the ever growing list. All kitchen counter-top areas must now be served by outlets with GFCI protection, regardless of the distance to any sinks. The exception that allowed outside outlets on a kitchen circuit has been dropped. The bathroom GFCI outlets must now be on a dedicated, 20 Amp. circuit, with no other loads connected. This means that you can not have any lights, exhaust fan, outside outlets, or any other outlets connected to a bathroom GFCI circuit. This requirement attempts to correct problems of bathroom circuits being overloaded with blow dryers, curling irons, etc. All the bathrooms' outlets in a house can be wired to a single 20 Amp. GFCI circuit, however. So, if there is more than one person blow drying at the same time in each bathroom, overloading might still be a problem if all the bathroom outlets are wired on a single circuit. |
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Another new requirement in the 1996 edition of the Code is a new section 410-57(c). This section was added to prevent the installation of outlets within the space of a shower or tub area. Earlier editions of the Code failed to address this issue. There still is no requirement as to the minimum space from a tub or shower area for an outlet, so one can still be located adjacent, but not within such a space.
If you have an indoor spa or "hot tub" the rules are very different. Such tubs generally are kept full at all times, with a recirculating filter and internal heater. A 5 foot minimum distance must be maintained from such tubs to any outlet(s)
Another new requirement can be found in section 210-8(a)(2). This section refers to "grade-level unfinished accessory buildings used for storage or work areas" or, in other words, a SHED. All outlets located in your shed, and other similar outbuildings are now required to be GFCI protected. All outdoor outlets were also added to the list in 1996. Previously, one could have a balcony or outlet mounted in the eaves, where direct access from grade level was not possible. Now, all such outlets must be GFCI protected. An exception for outlets dedicated for snow melting or de-icing equipment was added, so these are NOT required to be GFCI protected.
| 1996 saw the addition of another new section of the Code adding Article
625 for electric vehicle charging system equipment. This section requires
supply conductors to have GFCI protection for personnel. This requirement
can be satisfied by having a GFCI unit as part of the attachement plug
assembly. Underwriters Laboratories (UL) is currently working on standards
for the GFCI devices required by this new section.
In conclusion, the GFCI units have come a long way from a supplemental protection for swimming pool lights to being required in almost any area that can come in contact with water or wet conditions. Since water and electricity don't easily mix, these important safety devices should be viewed as good insurance against the uncertainty of the operating condition of premises wiring and appliances. To insure their safety and integrity, the test button should be utilized on a regular basis - at least once a month. TEST these GFCI units REGULARLY! YOUR LIFE MAY DEPEND ON IT! GFCI units are not surge-protectors, and may become inoperative after a lightning strike, or strong power surge. |
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1971: Outdoors (direct grade access), & within 15 feet of a swimming pool
1975: Bathroom receptacles
1978: Garages, Fountains
1981: Whirlpools, tubs, etc.
1984: Motels in bathrooms; replacements for non-grounded type
1987: Kitchens within 6' of the sink, (1) in a basement; boathouses
1990: All in unfinished basements; crawl spaces
1993: Wet bar sinks; Replacements in other required areas
1996: All kitchen counter-top outlets; dedicated circuits in bathrooms; All outdoor outlets, in sheds, balconies, whether accessible from grade level or not; Electric car chargers.
The author gratefully acknowledges the following sources of information for this file:
Electrical Contractor Magazine, Supplement, "The Evolution Of GFCIs," by George Flach (March 1994);
Changes to the 1996 Code, Seminar hosted by Gregory P. Bierals sponsored by Branch Electric Supply Co. (October 1995).
Practical Electrical Wiring (16th Edition) by Herbert P. Richter (deceased), and W. Creighton Schwan;
Captain Code: 1996 NEC; Important Revisions for Wiring Devices in the 1996 NEC National Electric Code, Pamphlet produced for LEVITON.
Based on the the book "Understanding the 1996 National Electric Code Changes" by Mike Holt.
National Electrical Code (NFPA-70) 1962, 1965, 1968, 1971, 1975, 1978, 1981, 1984, 1987, 1990, 1993, and 1996 editions.
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P.O. Box 1142 Salisbury, MD 21802-1142 Phone: 410-543-9956 or 800-234-1902 Fax: 410-219-9094 E-Mail KB@kbelectric.biz |