Avoiding Fires with AFCI's

parallel and series arcs in wires

What is an arc?
An arc is electricity jumping through the air to get from one wire to another. Arcing can occur at: a loose electrical connection (screw terminal or wirenut); a small break in a wire; or a break in the insulation of two adjoining wires. Arcing creates high intensity heat (it may exceed 10,000 degrees Fahrenheit) resulting in burning particles that may cause building materials such as wood framing and insulation to catch fire. When unintended arcing is occuring, it's called an arc fault. (Some devices create intentional arcs such as the ignitor on a gas stove.)

You may notice an arc when you insert an electrical plug. This is normal and not considered an arc fault. However, if sparks are shooting out of a wall socket after your hand leaves the plug, this is a serious condition that should be corrected.

What causes an arc fault?
Often unseen, arc faults can occur anywhere in the home’s electrical system including inside walls and within electrical cords. There are a wide range of conditions that may cause arcing.

Wire Degradation

  • Natural degradation through age.
  • Humidity or heat.
  • Extended mechanical stress.
  • Extended voltage stress.

Physical Damage

  • Poor wiring connections.
  • Animals chewing through wire insulation.
  • Wire punctured by nails from picture hanging or construction.
  • Power cord damaged from sharp bends or from furniture pressing on.
  • Power cord damaged from walking on them. (Never place one under a rug.)

What is an Arc Fault Circuit Interrupter (AFCI)?
AFCI's are a special type of circuit breaker with a microcomputer inside. The computer monitors the circuit looking for the tell-tale signs of arcing. When either a series or parallel arc is recognized, the AFCI shuts off the circuit before the arc can start a fire.

Where are AFCI's needed?
For homes built since 2008, the National Electric Code has required AFCI protection on every circuit in a bedroom, living room. dining room, family room, den, sunroom, recreation room, closet, hallway and any similar room.

What should you do?
AFCI's save lives by stopping house fires. If your electrical system does not have this protection, we recommend you add it.

Can you have both AFCI and GFCI protection on the same circuit?
Yes, we recommend that you do. This is accomplished using an AFCI circuit breaker and a GFCI receptacle.

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