Arc-Fault Safety in the Home

In recent years the National Electrical Code has expanded the use of Arc-Fault Circuit Interrupters (AFCI’s) in homes. There has been much debate among builders and electricians as to the need for these devices. Many claim that due to the number of nuisance trips and the added expense that these breakers are causing more problems than they are preventing. 

How AFCI’s came to be:

Standard type breakers that are most common in homes, trip for two reasons. First is a thermal overload, caused by to many appliances, lights or wiring problems on an electrical circuit. This is indicated by the amperage rating on the breaker (usually 15 or 20 amp). Second is a fault or direct short, caused when the line or hot lead directly touches a neutral lead or a source to ground. A source to ground can be a metallic appliance, water faucet and even a concrete floor. A standard residential breaker’s fault rating is usually 10,000 amps.

In the late 1970’s and early 1980’s, Ground Fault Circuit Interrupters (GFCI’s) were introduced due to the high number of people being electrocuted from a normally safe electrical installation. In many cases, electricity flowing through a human body was not enough to trip a standard breaker on an overload and/or a short. A GFCI was designed to measure the electrical current difference between the line or hot lead and the neutral. As long as the difference was zero all was well. When the difference became greater than 5mA (milli-amps) within 25ms (milli-seconds), the breaker or outlet would trip, thus indicating that some of the electrical current was going to ground and possibly through a human body. Currently GFCI’s are required at all kitchen countertops, bathrooms, near sinks, garages, basements, outdoors and any other location that can be wet.

While GFCI’s improved safety from electrocution, there was still, a high number of deaths due to electrical fires. AFCI’s were designed to monitor the electrical wiring in a home for arcs that could cause a fire. In many instances standard breakers would not trip from a fault due to the fact that there was not enough heat generated to trip a breaker on thermal overload nor was the short direct enough to trip the breaker. AFCI’s, monitor the electrical wiring for specific electrical sine wave characteristics, indicative of arcing. When these characteristics are present in an electrical circuit, the AFCI would trip. This could be caused by a loose electrical connection in an outlet or light switch, or by damaged insulation around the electrical wires. Early AFCI’s were prone to tripping whenever utilizing an appliance using a brush type motor, such as a vacuum cleaner, blender, circular saw or other power tools. Small electrical arcs, while not enough to trip a standard breaker, could generate enough heat to melt the plastic insulation on the wires, melt an outlet or switch and ignite wood framing, nearby drapes or other combustible materials. Is your electrical wiring safe?

In most instances your electrical wiring is safe, but there are a few things that you want to be aware of to insure your home and family are safe. We recommend if your home is older than 25 years, you should seriously consider replacing your existing electrical service with one using AFCI’s on all of the electrical circuits that will allow their use. First is to look… If you notice lights flickering or dimming then there might be a loose connection or a low voltage situation. A qualified electrician should be able to locate a loose connection and repair it. An electrician can determine whether a low voltage problem is due to problems in your home or caused by your electrical utility provider. Also look for outlets that are discolored, charred, broken or loose. This could be an indication of a loose connection, which can get worse if not corrected. Next you need to feel… Anytime you are near your electrical breaker panel, open the door and touch each breaker. If you feel one that is extremely hot call an electrician. Hot spots on your walls can be caused by faulty wiring and should be fixed immediately. If electrical cords and extension cords are hot, that is an indication that the cord size is too small, and it should be replaced by a bigger (not longer) cord. And last smell… If you smell plastic burning or something that you might think is electrical in nature, get it checked out immediately. Where there is smoke, there is a fire. Where there is the smell of electrical burning, a fire could be coming shortly. For more information you can check out this informative website: www.afcisafety.org.