<div dir="auto"><div>Here is Enphase's answer (or maybe Fronius was answering Enphase):<div dir="auto"><br></div><div dir="auto"><a href="https://enphase.com/en-us/support/arc-fault-demonstration">https://enphase.com/en-us/support/arc-fault-demonstration</a><br></div><div dir="auto"><br></div><div dir="auto">Also, their literature suggests that the risk of a DC arc fault occuring is far lower due to there being much less DC cabling exposed on the roof. With no long DC home runs, that would obviously lower the probability of an occurrence. I see where they are coming from, but we're talking about severity here, not probability. </div><div dir="auto"><br></div><div dir="auto">I have seen a few melted MC4 connectors at the panel to microinverter connection. The results seem to support Enphase's video where the arc is small and possibly intermittent, melting a hole in the connector housing, but falling short of an exposed flame. </div><div dir="auto"><br></div><div dir="auto">I think there is a twofold response that a microinverter manufacturer would make. The probability of DC Arc fault is reduced and severity is lower. That's a strong argument.</div><div dir="auto"><br></div><div dir="auto">Is anyone aware of a significant fire in a microinverter system caused by a DC arc fault? I assume there are anecdotes out there, but I haven't heard of any. On the flip side, I've seen some pretty gnarled DC conductor bundles melted together on string inverter systems with burned modules above them. </div><div dir="auto"><br></div><div dir="auto">That said, I would probably support more safety on the DC side of microinverters. If AC modules weren't so darn expensive, I'd probably go that direction. If PV DC leads were shorter I'd probably mount microinverters to module frames. If integrated AFCI was available on microinverters at a reasonable cost, that would be great. </div><div dir="auto"><br></div><div dir="auto">Jason Szumlanski</div><div dir="auto">Florida Solar Design Group</div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Feb 5, 2021, 5:40 PM Jeremy Coxon <<a href="mailto:jcoxon@sunwindpowerinc.com">jcoxon@sunwindpowerinc.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto">Very interesting video, now I know Fronius is pointing fingers at Micro manufacturers but the demo seems to back up their proposal to scrap the 80V limit. This is yet another reason we haven\u2019t used many Micro\u2019s on our systems.<div><br></div><div><a href="https://m.youtube.com/watch?v=H3c9GbLhQhY&t=4s" target="_blank" rel="noreferrer">https://m.youtube.com/watch?v=H3c9GbLhQhY&t=4s</a></div><div><br><br><div dir="ltr"><div>Jeremy Coxon NABCEP </div><div>Certified MWBE</div><div><br></div>Sent from my iPhone</div></div></div>_______________________________________________<br>
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