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A burned electrical outlet in a kitchen backsplash

Arc Fault Circuit Interrupters

Dear Mr. Electrician: What is the reason for Arc Fault Circuit Interrupters or AFCI? Answer: Arc Fault Circuit Interrupters provide an additional level of protection against fires.  Electrical arcs create heat and sparks.  If combustible materials are nearby, a fire could erupt.  Arc Fault Circuit Interrupter circuit breakers protect us from potential fire starters that we cannot see.  NOTE: Some text links below go to applicable products on Amazon.   As an Amazon Associate I earn from qualifying purchases. Many residential homes have wood frame construction.  The electrical switch and receptacle boxes in the walls are attached to wood framing members.  The electrical wiring runs through the wood framing.  Wood is a combustible material.  If heat and sparks develop inside the wall you would not know it until it becomes obvious. An early warning indicator for possible loose connections is blinking or flickering lights.  If you see lights flickering fairly regularly, you may have a loose connection somewhere or something else is going wrong.  Have a professional electrician look into it for you. A Series Arc or low current arc can be as a result of frayed power cords, old appliances, or loose electrical connections. A Parallel Arc or high current arc can occur from a screw or nail being partially driven into a live wire causing a poor connection to be made between two current carrying conductors.  Also known as a line-to-neutral arc. Line-To Ground Arc or ground fault indicates electrical current leaking to earth ground. A combination AFCI will protect against the three types of arcs. CAUSES OF ELECTRICAL ARC FAULTS An electrical arc can be caused by lightning of course and your grounding electrode system, if it is in good condition, should handle that. However other causes of arcing are usually not as obvious until some damage or a fire takes place.  For instance, an electrical receptacle with a loose connection may be fine until one winter you decide to plug a high wattage portable electric heater into it. The heater uses a lot of current to keep you warm.  With the extra LOAD on the electrical circuit, the loose connection that was fine for a few years now arcs each time the heater is on. I found the above electrical outlet inside of a kitchen cabinet for the over-the-range microwave oven.  It was obviously not installed by someone qualified.  In addition to the loose connection that caused the arcing and subsequent burning, there was no connector in the back of the box to protect the cable from the edges of the metal electrical box.  In fact the knockout was punched out, but is still attached to the box. The electrical box was also not grounded properly.  There should have been a ground wire connection directly attached to the metal box.  Instead the ground wire only connects to the electrical outlet.  Something else that was a code violation, the electrical box was not screwed to the cabinet, it was just floating. An AFCI circuit breaker would have tripped off long before the damage got this far. Click here to read my blog...