The arc-fault protection requirement only applies to DC circuits on or entering a building, with a maximum system voltage at or above 80 V. The system must be able to detect and interrupt series arc faults as described above (a failure in conductor continuity) and disconnect inverters or charge controllers connected to the fault (or system components within the arcing circuit). In addition, the equipment must not automatically restart after a fault and have a visual indicator that a fault has occurred. Opening the circuit stops the arc immediately, so this technology decreases fire potential.
While there are still very few choices of equipment available to meet these requirements, more are appearing. In the spring of 2012, SMA America was the first inverter manufacturer to provide arc-fault detection in its inverters. Fronius now offers its IG Plus Advanced inverters with built-in arc-fault detection. Microinverter and AC module systems less than 80 VDC are exempt from this requirement, as are ground- and pole-mounted systems that have no DC circuits inside a building. Arc-fault protection that is integrated into charge controllers is available, as well as breaker-like units that can be integrated into a combiner box.
Whether battling squirrels that chew on module wiring, or birds and rats that build nests under arrays, keeping critters away is an ongoing battle that, if lost, can result in electrical faults and decreased electric production. There’s now PV array pest-deterrent hardware available. Clips from Heyco (Sunscreen) and Spiffy Solar hold screening against the frames of modules, preventing animal access under the array. SnapNrack’s Edge Screen kit is available for its pitched-roof racks. Future building or electrical codes may require this; in the meantime, installers can save themselves a lot of headaches, callbacks, and liability by keeping the vermin at bay.
Another critical step in keeping PV arrays operating safely is keeping module wires, PV source circuits, and wiring for microinverters reliably secured and supported so the insulation isn’t damaged. Stainless steel and plastic clips for securing module wiring to frames are available from multiple manufacturers, including Arlington’s SC100, Burndy’s Acme, HellermannTyton’s E-Clips, Heyco’s Heyclip Sunrunner, and Thomas & Betts’ Ty-Rap. Heyco also offers a vinyl-jacketed stainless-steel cable tie—the Sunbundler—for PV wire management. Rack manufacturers SnapNrack, Schletter, and Legrand, and module manufacturers Lumos Solar and Silicon Energy, make racks with integrated wire management. On larger systems, cable tray, or similar products from manufacturers like SnakeTray, are making quality wire management easier than ever.
Rebekah Hren is an author, educator, and full-time solar addict. She works as a project engineer for ground-mounted solar farm developer O2 Energies in North Carolina, and as an instructor and curriculum developer for Solar Energy International. Rebekah is a licensed electrical contractor in North Carolina, NABCEP-certified PV Installation Professional, and an IREC-certified PV Instructor.
Go Solar California • gosolarcalifornia.org
Burndy • burndy.com
Canadian Solar • canadiansolar.com
Daetwyler • daetwylerce.com
Enecsys • enecsys.com
Enphase Energy • enphase.com
ET Solar • us.etsolar.com
Fronius • fronius.com
Helios SolarWorks • heliossolarworks.com
HellermannTyton • hellermanntyton.com
Heyco • heyco.com
Lumos Solar • lumossolar.com
Mage Solar • magesolar.com
MidNite Solar • midnitesolar.com
Morningstar • morningstarcorp.com
OutBack Power • outbackpower.com
PMC Industries • pmcind.com
Power-One • power-one.com
Refusol • refusol.com
S-5! • s-5.com
SolarBridge • solarbridgetech.com
Schletter • schletter.us
Schneider Electric • schneider-electric.com
Silicon Energy • silicon-energy.com
SMA America • sma-america.com
SnapNrack • snapnrack.com
SolarWorld • solarworld-usa.com
SunPower • sunpowercorp.com
Talesun • talesunusa.com
Thomas & Betts • thomasbetts.com
Trina Solar • trinasolar.com
Westinghouse Solar • westinghousesolar.com
Zep Solar • zepsolar.com
Zilla • zillarac.com