What is an Arc?
An arc fault is an unintended electrical arc, created by current flowing through an unplanned path. Arcing creates high intensity heating at the point of the arc. If prolonged, an arc can result in igniting surrounding material, which can become the cause of an electrical fire.
What causes Arcing within a Solar System?
Arcs can be caused by loose, damaged, or corroded wires, terminals, or any point at which the electrical conductors can take an unintended path. Arcs could result from damaged cables, ill-fitted connectors, broken PV-Modules, or other wiring issues.
What is an AFCI?
An arc-fault circuit interrupter(AFCI) is an electro-mechanical safety mechanism (or circuit breaker), that selectively distinguishes between a harmless arc (incidental to normal operation of switches, plugs, and brushed motors), and a potentially dangerous arc (for example: A lamp cord which has a broken conductor).
AFCIs are required by the National Electrical Code for most electrical circuits within grids or structures.
What is an Arc Fault?
An Arc Fault is the safety reaction and/or error notification supplied by a device that has an AFCI. In a solar system, AFCI Fault and reporting would come from the Inverter or Charge Controller.
What do I do, if I receive Arc-Fault notifications from my inverter?
Tigo advises our customers to have their system inspected for potential "leaks" or possible connector/wiring issues. Upon inspection, Tigo can work directly with the local installer to provide more information about Tigo Technology and it's role within the system.
Do Tigo MLPEs cause Arc-Faults?
Tigo MLPEs are fully self-contained and highly tested electrical devices that do not cause arcs within a system. However, there are a few scenarios in which a Tigo MLPE can contribute to nuisance Arc-Fault reporting:
- Incompatible Connectors - Always make sure that the connectors on the system are compatible. Tigo products use Stäubli MC4 rated connectors. If the existing connectors on the system are generic MC4 (or a different variety altogether), it can cause internal arcing between the connector nodes.
- Generational (inverter) Compatibility - If the Tigo MLPE was manufactured prior to 2017, it may not be compatible with modern AFCI products. This is important to know for older systems where the inverter has recently been replaced. The modern inverter may be too sensitive for the older Tigo product.
If this is the case, Contact Tigo Support for assistance, as there may be methods or software updates available for amending such systems.
For more information on inverter AFCI compatibility, see: Tigo's Letters of Certification and Compliance
- AFCI Updates - Inverter manufacturers often supply AFCI software/hardware updates for their products, created especially for inverters being used with MLPEs. Please check with the inverter manufacturer to see if there are any modern updates for the inverter.
- Damage to the Tigo MLPE - If the MLPEs on a system were installed incorrectly, experienced a harsh weather event, or there is an issue with local connectors/wiring, a Tigo product can become physically damaged. If you find damage, it is important to have the system fully reviewed by your installer, as any Arc-Fault caused by a Tigo MLPE would be considered a symptom (not the cause).