Arc Fault Circuit Interrupter (AFCI)
The National Electrical Code (NEC) defines arcs as “arcing faults resulting from a failure in the intended continuity of a conductor, connection, module, or other system component.” To increase fire safety of solar systems, the NEC requires solar systems installed on buildings to be equipped with an Arc Fault Circuit Interrupter (AFCI) (section 690.11 of the NEC) and for the system to visually indicate if an arc occurred. When an arc occurs the NEC requires that the system be restarted manually.
Why do arcs occur?
There are various reasons for why an arc can occur. Typical examples for solar installations are:
- Faulty system components
- Loose connections
- Installation errors
- Physical damage to equipment
- Damaged conductors
AFCI solutions for solar systems
Nowadays, most inverters have an integrated UL certified AFCI to comply with the NEC requirements - including the Fronius SnapINverter generation and Fronius IG Plus Advanced. These features are turned on by default. However, there are also third party solutions available on the market, which are compatible with Fronius product. Your solar installer can choose between the Fronius internal AFCI solution, or an external third-party AFCI solution.
The American National Electrical Code is not a national standard adopted uniformly across the United States. Each state and municipality must individually adopt sections, variations, or additions of the NEC as that state or municipality deems necessary. Your solar installer will work with an Authority Having Jurisdiction (AHJ) to verify the exact PV configuration needed to meet your community’s local standard. The AHJ is the local, state, or federal official designated responsible for approving equipment, installation, or procedure. The local AHJ is responsible for enforcing the local standards at any PV installation site. The Standard for Electrical Safety in the Workplace (NFPA) publishes standards to help provide some guidance as to this person’s roles and responsibilities.
Installers are instructed to follow manufacturer's guidelines for installation and maintenance of the PV components. However, final decisions regarding site specifics components and requirements for individual PV installations, as an industry standard, are the responsibility of those most familiar with the site, your installer and the AHJ.
Practically speaking, the installer is the only entity capable of determining if the combination of component parts that make up a PV installation leaves the site vulnerable to arc flashes.
Can I turn off the inverter integrated AFCI?
It's the installer’s responsibility to determine if AFCI is required in your jurisdiction; and if so required whether or not to use the Fronius integrated AFCI feature or a third-party solution. Since the feature is turned on by default, the installer can request a free AFCI Token for deactivating the feature, if the installer so chooses.
Access to this token is not a determination by Fronius that AFCI should or should not be activated on a particular site. The token is simply information, just like our manuals, of options within the inverter. It is still the responsibility of the installer to use appropriate and professional judgement and to follow all industry standards, rules, and regulations of the jurisdiction where the site is located.
What do I need to know as a home owner?
Homeowners who acquire a PV system through the purchase of a new home should have an installer check the PV system and to make sure the proper AFCI regulations are being followed.
If you would like to get free access to the AFCI Token, please contact Fronius Technical Support at firstname.lastname@example.org or (219) 734-5500