Arc fault detection

[ambe0241]

In NEC2014. Is DC side arc fault detection required in ground mounted PV farms not connected to a building. Also, is it required on ground mounted arrays that have the AC tie in on a building.

 

[SolarPro]

Yes. We break it down in this article "Understanding the NEC 2014 and Its Impact on PV Systems:"

Section 690.11 ?Arc-Fault Circuit Protection (Direct Current)?

Series arc-fault protection requirements for dc PV circuits were first introduced in NEC 2011. However, these requirements applied specifically to PV systems with a maximum system voltage greater than or equal to 80 Vdc, and with dc circuits on or entering a building. In NEC 2014, these requirements are expanded to all PV systems with a maximum system voltage greater than or equal to 80 Vdc, regardless of location. As explained in the ROP: ?PV arc faults in ground-mounted PV arrays can result in grass and brush fires. Such fires can result in deaths and significant property damage, which can be prevented with PV arc-fault protection.? Note that the arc-fault protective device must be listed for use in dc PV systems. The applicable product safety standard is UL 1699B, ?Photovoltaic (PV) DC Arc-Fault Circuit Protection.?

 

[beanland]

Real Product

Real Product

I just searched for "Photovoltaic DC Circuit Arc Fault Protection" and did not find a single device for sale. Can anyone provide a citation for a UL-listed device that is manufactured for this purpose?

 

[jaggedben]

I think you should play with your search terms a little more.

For string inverters, all of the major US manufacturer's have it integrated now. With SMA it is designated with a '-12' at the end of the model number. Power-One does it with a '-A'. With Fronius it is the 'Advanced' series.

For central inverters, there are combiners. Try "arc-fault combiner box" and you'll get results from SolarBOS and others.

Try "arc-fault charge controller" and you'll get the Midnite product.

 

[tom baker]

Washington is holding off on this requirement, from the May Electrical Currents:

Note from the Chief ? Photovoltaic Rules Delayed
During the past few weeks, several Washington State manufacturers involved in
the photovoltaic (PV) industry have contacted the electrical program. All
expressed concerns that the industry is not ready for new PV requirements in
the 2014 National Electrical Code (NEC) specifically, sections 690.11, Arc-Fault
Circuit Protection (Direct Current), 690.12 Rapid Shutdown of PV Systems on
Buildings and NEC 705.12(6), Wire Harness and Exposed Cable Arc-Fault
Protection. Each manufacturer has technical obstacles in complying with the
new NEC requirements by the July 1, 2014 effective date.
The electrical program conducted independent research and came to similar
conclusions. We discussed the issues with all four in-state PV manufacturers, other PV industry experts, and the State of
Oregon, which has already delayed implementation of NEC 690.11 until April 1, 2016 and NEC 690.12 until October 1,
2017. We conducted extensive online research and reviewed the Reports on Comments and Reports on Proposals for
the 2011 and 2014 NEC revision cycles. All three requirements are meant to increase electrical safety for PV systems and
in the future, no doubt will. However, by policy, I am granting a one-year delay, until July 1, 2015, in implementation of
all three requirements, allowing the Washington State PV manufacturers time to address each of these issues.
Enforcement will begin July 1, 2015. This reasonable approach will ensure an acceptable level of safety while not
hampering Washington State?s PV industry.