Selection of a DC Solar PV Arc Fault Detector

1. Executive Summary Arc fault current interruption (AFCI) is required on DC conductors of solar PV installations by NEC 2011 (rooftop systems only) and NEC 2014 (rooftop and ground mount systems). To meet these requirements, combiner boxes for central inverters will need to include arc fault detectors (AFDs) as well as other AFCI equipment. UL recognized AFDs greatly ease the process of listing a combiner box, and there are now a handful of UL recognized devices on the market. Beyond UL recognition, which focuses on arc detection but not real world performance, a desirable AFD needs to perform with a minimum of nuisance tripping while offering competitive cost in terms of both capital expenses (CAPEX or initial costs) and operating expenses (OPEX or operating and maintenance costs).