Ground-fault protection is the law of the land when it comes to protecting you from the risk of electric shock - and for good reason, too. GFCI receptacles, commonly used for bathroom receptacles, have saved many lives and could save more if they were more widely used. You can also provide GFCI protection to a circuit by installing a GFCI breaker in the service panel. The old movie scene of a radio dropping into the tub to electrocute the ill-fated bather could not happen in a bathroom properly wired with GFCI protection. Old hair dryers are especially dangerous in wet areas since they have no fault protection built into their design. New hair dryers do have protection; it is in the little box at the plug-in. Working with power tools, especially outdoors, is one of the most dangerous applications for electrical power. Whether using an old drill in the garage or working outside on the swing set, your feet are on conductive material. If the tool has a hot-wire-to-frame fault, current will flow from the tool into your hand, making the muscles contract, which in turns tightens your grip and makes it functionally impossible for you to release the tool. The current flow continues through your arm, body, heart and finally through your legs to the earth. If this happens on a ground-fault protected circuit, you will feel like somebody jabbed you with a needle. Immediately there after the GFCI will open the circuit and the current will stop. To make full use of these life-saving devices, you need to know everything about them.
How GFCI Receptacles Work
GFCI Receptacles, are not the grand mystery most people conceive them to be. They are actually very simple devices. General-purpose, 120-volt household circuits have current flowing to and from the load on two insulated wires: the white and the black. Power is brought to the load on the black wire, flows through the load and then returns via the white. As long as these two currents are equal, the GFCIs, is happy and provides power like a standard receptacle. But if some of the return current is missing, the GFCI will immediately open the circuit.
The logic is that if some of the electrons that leave the device don’t come back, they must be going somewhere else. Usually, this “somewhere else” is through a hapless tool holder to ground. The actual amount of missing current needed to trip the GFCI is 4 to 6 milliamps (thousandths of an amp). This is the maximum amount of current the normal person can take without his or her heartbeat loosing its rhythm. Instead of a steady thump, thump, thump, a shocked heart starts beating to an irregular rhythm. Such syncopation is great for music but deadly for hearts.
GFCI Limitations
The use of GFCI devices is obviously not a substitute for using good common sense. If you have your hairdryer, toaster or other electrical apparatus powered through a GFCI receptacles or GFCI-protected extension cord, this doesn’t mean you can do dangerous things. It is possible to have an AC-operated tool powered through a GFCI and still get electrocuted. GFCI’s only operate when they sense a ground fault (short through to ground). If the operator puts himself between the hot wire and neutral without any current flowing to the earth, the GFCI will not open the circuit. As a rule, DO NOT use any AC-powered tool while you are standing in water. NEVER use any electrical tool if you or the tools are wet.
Your GFCIs Options
An electrician can install two types of GFCIs in your home: GFCI circuit breakers and GFCI receptacles.
The electrician will install GFCI circuit breakers in the electrical service panel like standard breakers, but he or she also must connect the breaker’s integral pigtail to the service panel’s neutral bar. The electrician will then connect the neutral/white branch circuit wire to the breaker, not to the neutral bus. Use this type of GFCI if all receptacles on the circuit require ground fault protection.
GFCI Breakers
GFCI circuit breakers have two main disadvantages: cost and inconvenience. Also, if something trips the circuit, you must reset the GFCI breaker in the service panel. This can be a hassle if you are in an upstairs bathroom when the breaker trips and your service panel is in the basement or garage. However, that inconvenience is a breaker’s most valuable asset for longevity: since they reside far from high moisture areas, they live longer than GFCI receptacles that are installed at the point of use.
On top of the GFCI breaker there will be a TEST button. Once installed properly, pressing the button places a preset current imbalance on the line to verify that the breaker will trip off as it should. When tripped, the breaker arm goes to the half-off position and the circuit loses power. Once tripped, the GFCI circuit breaker will not reset unless the breaker is first turned al the way off before it is turned back on again. Many no-power service calls are made to electricians when the only problem was the owner did not turn the breaker all the way off before turning it back on.
GFCI Receptacles
GFCI receptacles are installed like ordinary outlets except that you must pay special attention to which terminals are marked “line” and which are marked “load.” Assuming you correctly connect the leads from the service panel to the line terminals, anything connected to the load side will be protected. For example, if you have five receptacles on a circuit and want to protect all of them, install the GFCI receptacle in the first outlet to protect other devices downstream. Be sure to label the downstream receptacles “GROUNDFAULT PROTECTED.” Most GFCI receptacles come with stickers for this purpose. Use this type of ground fault interrupter whenever possible, with one exception: outdoor receptacles.
Outdoor receptacles with cords attached “full time” must be GFCI protected and have a lid that keeps the connection waterproof while the cord is plugged into the box. This outdoor in-use receptacle cover is commonly referred to as a “Bubble Cover “. Electrical Marketplace offers bubble covers in one and two gang configurations. This accomplishes the same thing as a GFCI circuit breaker for a fraction of the cost.
Electrical Codes that Govern GFCI
The National Electrical Code (NEC) allows a GFCI to be installed in place of ungrounded two prong receptacles. A GFCI receptacle will work without a separate ground wire. Although a three wire GFCI protected outlet is safest, a ground fault protected two-wire receptacle is better than an unprotected one. Here are other GFCI code requirements worth remembering.
Garages — All 120 volt receptacles in garages must have GFCI protection unless they are not readily accessible. “Not readily accessible” refers to a receptacle located on the ceiling for a garage door opener or a single receptacle for an appliance occupying dedicated space, such as a freezer. (Even though it’s not required, Electrical Marketplace recommends operating a garage door opener from a GFCI receptacle, as it can save the opener from lightning damage.)
The garage rule, which dates back to 1981, holds true for unattached accessory buildings as well when their floors are at or below grade. This rule was put in place because the garage and outbuildings are the mostly likely places for you to plug in handheld power tools such as grass trimmers, electric lawnmowers and hedge trimmers.
Workshops — Of special interest to the DIYer. Your workshop, when in a garage or outbuilding with a floor at or below grade, must have GFCIs protection on the 120volt receptacles. A 1999 change to the code dropped the word “unfinished” in reference to workshops and storage areas in garages and accessory buildings. So don’t think that just because your shop has a finished floor it meets the code. Most workshops have a concrete floor, which tends to hold moisture, which increases shock potential and isn’t considered “finished” for the code. Basement workshops follow the rules for basements (see below).
220V outlets aren’t specifically addressed in this part of the code. However, in a workshop setting they’re generally for large machinery like table saws. Because the outlets will not accept a standard 120volt appliance cord, they fit the “not readily accessible” exception.
Outdoors — All 120 volt receptacles installed outdoors, including those installed in outside accessory buildings, must have GFCI ground fault protection. In addition, if they have a “fulltime” plug in them, they must have a special lid that can close to keep the plug connection watertight (see XXXX Electrical Marketplace product OB-UI In use weather proof receptacle cover). One exception is an outdoor receptacle on its own circuit that is not readily accessible and is used to power a heater cable for melting ice and snow. If you are working outside and using the outlet on an older house that has no ground fault protection, use a GFCI protected extension cord. Receptacles in outbuildings also need GFCI outlet protection.
Basements — Receptacles in unfinished basements must be GFCIs protected, with two exceptions. The first is a single receptacle connected to a dedicated branch circuit that supplies a corded appliance, such as a refrigerator or a sump pump. The second is a laundry circuit, the 120volt circuit to the washer.
Note that the flooring is what determines whether the basement is finished or not. A concrete floor in a basement workshop is not considered finished as far as the electrical code is concerned. It’s too likely for the concrete to be damp, thereby increasing shock hazard. An inspector will be looking for several layers of flooring material on top of the concrete before signing off on your workshop.
Kitchens — Current NEC code now requires that all countertop receptacles (it used to be only those within 6 ft. of a sink) must be GFCI protected. That includes kitchen islands and peninsulas. Since two separate circuits must feed the countertop receptacles, Electrical Marketplace recommends that kitchens with one GFCI receptacle to the left of the kitchen sink and one GFCI outlet to the right of the sink to balance the load. Outlets within 6 ft. of a wet bar sink also need GFCI protection.
Bathrooms — All receptacles in bathrooms must have GFCI protection. Bathroom outlets are intended for hair dryers, electric razors, etc. These GFCI outlets must be within 3 ft. of the sink bowl and on the same wall as the vanity or on either wall to the side of the sink. This is to accommodate the cord lengths on common bathroom appliances. Double sinks can have a receptacle on each side or one receptacle in the middle.
National Electrical Code states that receptacles in the medicine cabinet or light do not count as the required receptacle. If you use them, they must be both grounded and GFCI protected. Electrical Marketplace suggests that you cut them dead to prevent accidents.
Current code now allows two baths to share the same circuit — but Electrical Marketplace says don’t do it. Some hair dryers can pull over 1,800 watts, which means that just this single appliance can max out a circuit and the breaker is going to kick as soon as anything else pulls current. Having two bathrooms on one breaker is dangerous.
Current code also allows a circuit that feeds a single bath to also feed any other 120volt load in the bath. Again, Electrical Marketplace says — don’t do it.
GFCI Types
GFCI receptacles come in many different configurations. However, the two most common offered through Electrical Marketplace will be types resembling either a receptacle or a single-pole 120-volt circuit breaker-both available in 15-and 20 amp designs. Less common are 30-, 40-, 50- and even 60 amp GFCI breakers, although they do exist. Due to their low cost and ease of installation, receptacle GFCIs are the most common GFCI protection devices. They obtain power from a standard circuit breaker in the main panel and the GFCIs are placed ate their point-of-use, such as the kitchen and bath. Many people prefer to use receptacle GFCIs inside the house and circuit breaker types for the outside power.
GFCI Receptacle Quality
The most common complaint that Electrical Marketplace gets concerning GFCI receptacles is their short life span. Though some do last a long time, a small few are bad upon installation and others last only a few years. However better grade GFCI receptacles are available. Look for SPEC grade, commercial grade, and hospital grade. These are much higher quality units for just a few dollars more. Electrical Marketplace offers GFCI receptacles in many colors, including brown, ivory, white, gray, almond and black.
Where To Use GFCI Receptacles
There are certain locations throughout the house and residence where the NEC and common sense require that GFCIs be used. For example, every small appliance outlet along the kitchen counter and at a wet bar. Bathrooms are always wet, so all receptacles in the bathroom need GFCIs protection. The over head bathroom fan, light, or combination thereof, will need GFCI protection when they’re mounted above the bath or in the shower enclosure. In addition, the unit the GFCI protects should be rated for wet locations. Outside receptacles and those in outbuildings need GFCI protection. Garages, crawlspaces, boathouses, areas around swimming pools, spas, and hot tubs and unfinished basements all need GFCI protection.
Where not to use a GFCI
So, if GFCIs are so great why don’t we use them on every receptacle in the home and never have to worry about being electrocuted? Well, as you might have suspected by now, if GFCIs trip with current imbalances as low as .006 amp, they might just trip when they are not supposed to. Utility lines occasionally have noise and power spikes that come into the house and can trip a ground-fault interrupter. Tools and appliances that are especially noisy will trip a GFCI as well. So you do not want to have any circuit GFCI-protected that cannot afford to be without power freezers, refrigerators, sump pumps, and medical equipment are a few examples of appliances you may not want on a circuit that is GFCIs protected. In addition, lights, unless required by code because they are in specific areas, should never be on a GFCI circuit. GFCIs cannot be used for ranges, ovens, cooking appliances, clothes dryers and other appliances with grounded neutrals connected to the frame of the appliance.
GFCIs and Old-House wiring
GFCIs are required to be installed whenever a receptacle, grounded or ungrounded, goes bad and needs replacement, if the receptacle is in a location where GFCIs are currently required. Code allows GFCIs to be used without grounds. Its true that the old wiring wont have a grounding wire to attach to the GFC, but a GFCI works whether the ground is there or not. If a GFCI feeds ungrounded outlets from its LOAD terminals, those receptacles must be labeled GFCI PROTECTED and NONGROUNDED.
Testing GFCI Protected Outlets
Testing is of primary importance with GFCIs since their sole purpose is to save lives. All GFCIs should be tested monthly with their own TEST button and the receptacles they protect should be tested with a plug-in GFCI tester. Besides having the push button for testing the life-protection circuitry, most GFCI testers also have light indicators to analyze the wiring attached to the unit itself. This is also an important test because sometimes a GFCI may test right even though it is wired wrong. In situations like this, the manufacture will not warranty the unit.
The test buttons on a GFCI breaker, a GFCIsreceptacle, and a GFCI tester all work differently. The tester places leakage current to bare wire, grounding system. Therefore if the ground is missing, the GFCI outlet may not trip when the TEST button on the plug-in tester is pressed. When the TEST button on the breaker is pressed, it places a leakage current from the line-side hot directly to the neutral bus. Therefore, a GFCI breaker only needs to have a pigtailed wire connected to the grounding bus for it to be tested. A GFCI receptacle places leakage current from load-side hot to line-side neutral to simulate a fault condition. When the test button opens the circuit, the circuit is opened differently when comparing the breaker to the receptacle. A receptacle GFCIs will open both neutral and line terminals. Therefore, even if the hot and neutral wires are reversed on the GFCI, it doesn’t make any difference since both lines are opened. However, the GFCI breaker only opens the hot line-the neutral stays intact. If the breaker has been wired backwards, the intact line is now the hot line and current can still go to the load.
Installing GFCI Receptacles
The outlet box where the GFCI Receptacles go in must be a deep box, otherwise there will not be enough room for both the box and the wiring. The following are some considerations to keep in mind when installing GFCIs:
- Never install a 20-amp GFCI on 15-amp circuit.
- Always be sure that the LINE and LOAD are not switched. LINE always connects to the incoming feeder cable. If there is more that one cable in the box then you will have to measure each cable, black to white, to determine which is the feeder.
- The LOAD terminals are always connected to any down-stream receptacles that need to be ground-fault protected.
- If a second cable goes to a light or another receptacle that is not ground-fault protected, then it must splice onto the feeder cable before the feeder connects to the LINE terminals of the GFCI receptacle. To do this attach a pigtail to the splice of both the black and white conductor splices, and use the pigtail to jump to the LINE terminals of the GFCI receptacle.
Follow these steps to safely install a GFCI receptacle:
- Remove the electricity from the circuit you are working on by turning off the breaker or pulling out the fuse.
- Remove the old receptacle. If the wires are not coded, label each wire as you remove it.
- All attachments to the GFCI itself are done with the stripped wire end formed into a half loop then inserted over the screw and tightened down. Attach the black wires to the brass screw. Attach the white wires to the LINE silver screw.
- Attach the bare ground wire to the green grounding screw terminal on the GFCI receptacle.
- When splicing is done, push the wires neatly back into the box with your fingers. If you did it right the wires should accordion neatly back into the box in a “Z” pattern. Attach the receptacle to the box.
- Attach the cover-plate to the GFCI, turn power on and press RESET button. Then make sure the receptacle is good by pressing the TEST button, which should trip and remove power from the receptacle.