AFCI Compliance

NEC 2014 code requires PV systems to have arc fault circuit interruption (AFCI) protection. AFCI protection is achieved by detection of an arc and immediate DC shutdown, at the string, combiner, or inverter level. Some inverter manufacturers have implemented solutions into their products, however some solutions experience false detection known as 'Nuisance Tripping'.

There are 2 possible triggers for AFCI, resulting in DC disconnect:

  1. Actual arc detection
  2. False trip due to noise on the DC line, incorrectly interpreted as an arc.

Research by Sandia National Laboratories identified multiple causes of nuisance tripping, most of which were unrelated to optimizers. A detailed report is available here.

Tigo's TS4 line of product can be divided to 2 groups when it comes to AFCI:

  • TS4-D, TS4-M, TS4-R-M: these units are 100% passive and behaving just as standard modules, therefore don't have any effect on AFCI devices whatsoever
  • TS4-S, TS4-R-S, TS4-O, TS4-R-O and TS4-L and JES/HBF Smart Modules: these units are not passive, and therefore being thoroughly tested for compliance 


As of February 13th 2017, Tigo has identified the following combinations:



  • 3 phase inverters with Tigo TS4 & TS4-R (all models) = compatible

Ginlong Solis

  •  1 phase and/or 3 phase inverters with Tigo TS4-S, TS4-R-S, TS4-O, TS4-R-O = compatible


  • Smart Modules = compatible


  • SolarRiver TL-US and TLA-US with Tigo Smart Modules = compatible


  • Huawei SUN2000-XXKTL-US with TS4-S, TS4-R-S, TS4-O, TS4-R-O and TS4-L = compatible


  • PVI 23TL/28TL/36TL 3-phase inverters with TS4-S, TS4-R-S, TS4-O, TS4-R-O, TS4-L = compatible


FE or IG Plus A:

  • Smart Modules = Compatible, up to 15 modules per string (Trinasmart up to 260W or similar)


Other Inverters with AFCI

Other inverter types are being tested for AFCI compatibility. If you have a specific question regarding an inverter equipped with AFCI that is not listed above, please contact us via email:


Retired Products

*ES50, ES75, ES110 and ES170 are retired product since early 2013. The ES series was fully compatible with all the inverter technologies which were available on the market at the time of manufacturing. As of this date, they are incompatible with AFCI devices.

**2ES50, 2ES75 are retired products since mid 2016. The 2ES series was fully compatible with all inverter technologies and AFCI devices which were available on the market at the time of manufacturing.

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