What is an Arc-Fault?
An arc-fault forms when a conductor is interrupted and a spark/ark forms. If heat forms and is high enough, it may cause a fire.
What Causes an Arc-Fault?
Arc-faults in PV systems can occur due if the system is poorly installed or the components used were faulty or damaged. Even if everything was installed correctly and all of the equipment was in good condition, if something occurs later in time that damages the PV system, you could have an arc-fault form.
What is PV Arc-Fault Protection?
In simple terms, arc-fault protection is any device that protects against fire hazard associated with DC wiring on solar PV systems. Aside of safety, arc-fault protection is important in order to be compliant with the 2011 NEC code, which requires detection and interruption of “arcing faults resulting from a failure in the intended continuity of a conductor, connection, module, or other system component.”
Look for inverters with AFCI (Arc Fault Circuit Interrupter) to provide arc-fault protection and to be compliant with NEC 2011 code. Note that not all states require this, so check your state’s codes.