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Ground Fault Circuit Interrupters - Whose Fault Is It, Anyway?
The term Ground Fault Circuit Interrupter (GFCI) is likely familiar to you. But did you know that a GFCI is a device that, when properly installed, provides you and your family with enhanced protection against electrical shock? And now, there is a new phrase to get familiar with: Arc Fault Circuit Interrupter (AFCI).
According to the National Fire Protection Agency (NFPA), every year there are about 40,000 house fires accounting for more than $500 million in property damage attributable to electrical system malfunctions. Three hundred or more deaths and nearly 2,000 injuries result from these fires in a typical year. AFCI devices are designed to reduce those statistics.
So, whose fault is it, REALLY? Here is a bit of a primer on "fault" protection: why it matters, what to look for, and what to expect. And why does the "I" matter so much?
Essentially, a fault in an electrical system allows current to fl ow someplace where it should not.
A GROUND FAULT provides an opportunity for current to flow from its source (the electrical circuits in your home, for example) to "ground" which, in most cases, is the shortest path to good old mother earth. Putting your hand in a sink full of water while holding your hair dryer is one good way to create a GROUND FAULT. Another would be to stand in a puddle of water in your garage while operating an electric drill. Fortunately, thanks to GFCI devices, when a GROUND FAULT is detected by the device it trips the circuit breaker (or clears the fault) almost instantaneously, within a few thousandths of a second, so the GROUND FAULT CIRCUIT (GFC) through your body is INTERRUPTED (GFCI). Because the device is so quick to react, you survive. While GROUND FAULTS are not often the cause of a fire they have been responsible for many deaths and injuries. The "I" is the act of interruption, that’s the life-saving step.
GFCI devices have been required by the National Electrical Code (NEC) for many years. Gradually, the requirements have expanded. In 1973, for all new construction, most outdoor outlets required GFCI protection. In 1978, bathroom outlets were added. In 1978 garage outlets, in 1987 kitchen outlets and in 1990 all outlets in crawl spaces and unfi nished basements. While the NEC only requires GFCI device installation in new construction, if any of these areas of your home are substantially renovated, most local codes would require upgrading the electrical circuits to include GFCI protection. GFCI devices come primarily in two forms, one which is part of the outlet (or receptacle) and the other which is a replacement for the circuit breaker in the main electrical distribution panel (sometimes called a load center).
Those of the former type include test and reset buttons on the outlet itself. For the latter type, the test button is on the breaker, in the panel. These devices should be tested monthly.
The cause of many electrical fires is a different kind of FAULT, an ARC FAULT. Essentially, an ARC FAULT is current flowing between two conductors (individual wires carrying electrical current). Most household circuits have either two or three conductors in one cable serving each circuit. An ARC FAULT may also occur when there is a loose connection at an individual electrical device such as a switch. When an ARC FAULT occurs, the conductors and devices in the vicinity will heat up, sometimes to very high temperatures, causing any adjacent combustible material to ignite, leading to a fire.
An Arc Fault Circuit Interrupter is quick to respond. The ARC FAULT CIRUIT (AFC) is INTERRUPTED (AFCI). The overheating does not occur and a fire is prevented. Again, the "I" is the important step, to prevent fires and save lives.
Vermont, recognizing the value of AFCI protection, took action in 2001 and required AFCI protection in ALL living areas, in new construction. The NEC fi rst required the installation of AFCI devices in 2002, in bedrooms, in new construction. You can expect the NEC to expand AFCI coverage requirements in the near future.
AFCI devices are primarily at the main electrical panel (load center) as a circuit breaker. Outlets protected by AFCI devices should be so labeled, in the living space in which they are located.
GFCI and AFCI devices help make our homes safer electrically. If you have an older home that predates any of the GFCI or AFCI installation requirements, we recommend that you install these devices. While it is not required by code for an older home, these are proven devices that save lives and property. If you already have a grounded electrical system (typically characterized by three prong outlets), the installation of these devices is relatively straightforward.
There is a caution for an older home, however. If the other outlets throughout your house are two prong devices (these accept only plugs with two prongs, not the more contemporary ones with a third, cylindrical, grounding prong) you probably have a wiring system using only two conductor cable; some folks will refer to it as an ungrounded system.
Without the third wire in the cable (for the third prong, which is a ground) most GFCI and AFCI devices will not function properly when installed on that type of circuit. To function properly, a new cable (two conductor, with ground) will need to be installed from your main electrical distribution panel (load center) to the location of the device. Thus, the installation process becomes more complicated and expensive.
All installations of GFCI and AFCI devices should be performed by a licensed electrician and their proper operation should be demonstrated when the installation is complete.
So, in the end, it’s not really anyone’s fault. But, faults in an electrical system are dangerous and there are some devices that will minimize that danger. Those devices, when properly installed, are a good investment for your home.
Electrical problems are one of the most common sources of house fires every year. To keep your home and electrical system safe:
Have all work done by a licensed electrician.
Install AFCI and GFCI devices, if your home doesn’t have them.
Test AFCI and GFCI devices monthly.
If your home is more than 20 years old, have all circuitry tested.
Test your smoke and CO detectors monthly
Criterium Engineers, Copyright © 1999