Electrical Arc Fault Circuit Interrupters or AFCIs are protective devices that are capable of responding to overloads of power or short
circuit situations. They prevent both fire and shock. This circuit breaker helps to prevent arc faults in a home that is the leading cause for electrical wiring fires. Each year in the United States, over 40,000 fires occur as a result of home electrical wiring resulting in 1,400 injuries and 350 deaths. This makes a home inspection imperative to keep the home as safe as possible and to prevent any untimely circumstances such as an electrical fire from occurring.
AFCIs resemble a Ground-Fault Circuit Interrupter in that they both have a test button on them. They are both designed to protect against electrical shock, but AFCIs primarily protect against electrical fires. Some outlets may have both a GFCI and an AFCI on it especially in areas where water can occur such as a wet bar, bathroom, laundry room or kitchen.
AFCIs should be on top of everyone’s home inspection checklist as since 2008 National Electric Code requires new and renovated homes to have them installed. They have been field tested and the National Association of State Fire Marshals, U.S. Consumer Product Safety Commission and Underwriters Laboratories all agree that AFCIs are both reliable and effective in preventing electrical fires in the home.
AFCIs are required in any new or remodeled home that has an outlet or fixture such as a dining room, living room, den, family room, library, bedroom, sunroom, rec room, closet, hallway or other living space.
How Do AFCIs Work?
Ultimately, when an electrical switch is closed or opened, an arc or discharge of electricity across a circuit occurs. These unintentional arcs can occur as a result of damaged wires or cores or loose connections. These arcs can lead to sparking, igniting and high temperatures. They are helpful at protecting against fire by closely and continuously monitoring the electrical current within a circuit and shutting it off when unintended arcing occurs. They are designed to distinguish between unintended arcing and the type that occurs when a switch is running. AFCIs should be tested annually and by any home inspector.
Pros & Cons of AFCIs
Unlike conventional circuit breaks that only respond to overloads, AFCIs are selective in choosing unintended arcs that can cause damage. When they are detected the AFCI opens and de-energizes the circuit which reduces its risk for fire. It should never trip during a normal arc, which occurs when a plug is pulled from a receptacle or when the switch itself is opened. AFCIs also don’t interfere with smoke alarms or appliances. They are state of the art devices that identify problems that current circuit breaks are not designed to do.
With any type of device there will always be positive. While AFCIs are designed to protect against electrical arc faults, they sometimes do give false positives identifying normal behavior as an arc fault. This can occur often during a thunderstorm. This tripping can result in overall lowering of effectiveness, but not so much that they are not recommended or required to be installed in new or renovated homes.
Another con is that AFCIs do not provide specific protection against any glowing connection, high or low line voltages or excess current. Glowing connections occur when a high electric current exists in a large resistance object. This energy can generate temperatures that are well above 1000 degrees Celsius. This can ignite anything flammable and quickly.
Bad wiring can occur in defective AFCIs. A home inspector can accurately alert a homeowner of this problem and suggest ways to repair the situation and in a timely manner. Also, an AFCI cannot detect high line voltage that occurs as a result of an open neutral in a multi-wire branch circuit which is energized as a part of a 120-240V process. If this neutral is broken then the devices that are connected to the 120 V leg to the neutral can experience excess voltage. To go with that, they also do not detect any low line voltages which can cause electro-mechanical relays that continuously turn off or on the circuit. If a current is flowing through the load, it can cause arcing which can oxidize, melt or pit the contact. A power fault circuit interrupters can help in this situation and may be a suggestion that a home remodel inspector may suggest.
Types of AFCIs
Different AFCIs work better in different places in the home. This means that help of a qualified electrician or professional home inspectors can better assist you in the planning and installation process of protecting your home against electrical fires.
A branch/feeder type of AFCIs is intended to be installed at the origin of a branch feeder at a panel board. It protects the branch circuit wiring or the feeder wiring or even sometimes both from any unwanted arcing effects. It limits protection to the branch circuit extension wiring and can be a circuit-breaker type device.
The combination type AFCI works to protect the downstream branch circuit wiring and any power-supply cords associated with it. The outlet branch circuit type of AFCI is installed at the first outlet in a branch circuit and works to protect any upstream branch circuit wiring. It can be installed with or without a receptacle.
The outlet circuit type of AFCI is installed at a branch circuit outlet or an outlet box. It works by protecting cord sets or power-supply cords that are connected to it.
Cord type AFCIs are plug-in devices that connect to receptacle outlets and protect the power-supply cord that is connected to it from any arcing. A portable type of AFCIs is intended to be connected to an outlet and works by protecting the power-supply cord from unwanted
Ultimately the cost of enhanced electrical fire protection in the home is directly affected by the size of the home and the number of circuits installed or needing to be installed. AFCI-type circuit breakers typically cost about $35-$40 each. Especially during a home remodel, this expense should be budgeted in as it is necessary, required by National Electric Code and ultimately, a way to better protect your home and the person within it. A qualified home inspector can also give you more specifics on the overall cost for replacing or installing these in your home.
Many homeowners have found that installing an arc-fault circuit-interrupter (AFCIs) as easy. The project starts by determining what circuits you will need to protect with these AFCI breakers. Check your specific breaker panel for the brand you will need. When working within the breaker panel, always shut off the main circuit breaker. Remember that the wires leading into the panel itself are always energized even if it is turned off. Wear rubber-soled shoes and use tools with rubber handles to protect yourself further.
After shutting off the main circuit breaker, remove the panel cover. Pull the circuit breaker that you want to replace from its slow and remove any black wire from the breaker. Follow the black wire that you already disconnected to where the cable enters the box. Follow the white wire from that same cable and disconnect it. Turn the AFCI breaker to an off position and loosen the terminal screws (usually there are two).
Connect the white circuit wire to the breaker terminal that is labeled either white or panel neutral. Next, connect the black circuit wire to the terminal labeled black or load power. Connect the coiled white wire to the neutral bus bar (same place that you remove the white neutral wire before). Install the new breaker by snapping it into place and making sure that the connections are tight. Replace the panel cover. Lastly, turn on the main breaker and the AFCI breaker and test the breaker by pressing the test button on the front. If the breaker is running properly, the breaker will trip open.