The UL Standard for AFCIs (UL 1699) defines an arcing fault as an unintentional arcing condition in a circuit. Arcing creates high intensity heating at the point of the arc resulting in burning particles that may over time ignite surrounding material, such as wood framing or insulation. The temperatures of these arcs can exceed 10,000 degrees Fahrenheit. Repeated arcing can create carbon paths that are the foundation for continued arcing, generating even higher temperatures.
Typical Causes of Arc Faults
Worn electrical insulation
Wires or cords in contact with vibrating metal
Overheated or stressed electrical cords and wires
Misapplied or damaged electrical appliances
Why do we really need AFCIs?
Smoke alarms, fire extinguishers and escape ladders are all examples of emergency equipment used in homes to take action when a fire occurs. An AFCI is a product that is designed to detect a wide range of arcing electrical faults to help reduce the electrical system from being an ignition source of a fire. Conventional overcurrent protective devices do not detect low level hazardous arcing currents that have the potential to initiate electrical fires. It is well known that electrical fires do exist and take many lives and damage or destroy significant amounts of property. Electrical fires can be a silent killer occurring in areas of the home that are hidden from view and early detection. The objective is to protect the circuit in a manner that will reduce its chances of being a source of an electrical fire.
How is an arc fault detected?
Unlike a standard circuit breaker detecting overloads and short circuits, an AFCI utilizes advanced electronic technology to “sense” the different arcing conditions. The end result is the detection of parallel arcs (line to line, line to neutral and line to ground) and/or series arcs (arcing in series with one of the conductors).
In essence, the detection is accomplished by the use of advanced electronic technology to monitor the circuit for the presence of 'normal' and 'dangerous' arcing conditions. Some equipment in the home, such as a motor driven vacuum cleaner or furnace motor, naturally create arcs. This is considered to be a normal arcing condition. Another normal arcing condition that can sometimes be seen is when a light switch is turned off and the opening of the contacts creates an arc.
A dangerous arc, as mentioned earlier, occurs for many reasons including damage of the electrical conductor insulation. When arcing occurs, the AFCI analyzes the characteristics of the event and determines if it is a hazardous event. AFCI manufacturers test for the hundreds of possible operating conditions and then program their devices to monitor constantly for the normal and dangerous arcing conditions.
The Siemens Advantage
An AFCI serves many electrical safety functions including arc detection, over current and short circuit protection. When your AFCI trips, do you know why? Was their an arcing condition, ground fault, over current, or short circuit? Trouble shooting the cause of an AFCI trip can be difficult. Beyond the industry leading arc detection technology, the Siemens AFCI includes many other features including the industry exclusive LED trip indicator. The Siemens AFCI will tell you why it tripped! It will also hold that information in its memory for up to 30 days if you require an electrician to come to your residence to correct the condition. Knowing the cause of the trip greatly reduces trouble shooting time and tracking down the cause of the trip. Siemens also offers the smallest sized AFCI in the market, leaving more wiring room in your load center.
Return or exchange within 30 days from the delivered date.
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