Interesting. I installed some of those manufacturers between those dates. The company I was working for from 2010 to 2019 is no longer in business, and I lost all my email from there, so don't even have good records of the customers then, though I probably have all of the permit drawings on some old hard drive still. These installs were in Colorado, so a much drier climate than Vermont, but still, there are wet days...
Zeke On Tue, May 5, 2026 at 1:25 PM <[email protected]> wrote: > Send RE-wrenches mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > > http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of RE-wrenches digest..." > > > When responding to posts within the Digest, be sure to restore the > Subject: line to the exact original, and please edit out any extraneous > lines from the quoted message. > > > > Today's Topics: > > 1. PSA: Schuco recall and broader polyamide backsheet defect > (2010-2014 era) (Nicholas Ponzio) > 2. Fortress Envy CTs on 200 amp wire (William Miller) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 5 May 2026 12:14:48 -0400 > From: Nicholas Ponzio <[email protected]> > To: RE-wrenches <[email protected]> > Subject: [RE-wrenches] PSA: Schuco recall and broader polyamide > backsheet defect (2010-2014 era) > Message-ID: > < > cadr8m8jumpgdtzayotwobajqzar-hgcjhi1_9v1ht4ha8xl...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Wrenches, > > Sharing a finding from this week that I figure plenty of you are running > into and may not have connected the dots on. I know I hadn't until > yesterday. > > We pulled an old array off a roof in Vermont. Not our installation. Modules > were Schuco, vintage ~2010. Client asked about reinstalling vs. replacing, > and that question sent me down a rabbit hole. > > It turns out Schuco issued a formal product safety warning in 2022 covering > modules delivered from 2010 to 2014. The polyamide backsheet from a > specific supplier can develop chalking and cracking along the internal cell > connector. When this happens, the panel frame can become electrically live. > Critical detail: inverter shutdown does NOT eliminate the hazard while the > panels see sunlight. The manufacturer's own remediation guidance is to > uninstall and dispose of panels. UK Government issued a formal product > safety alert (2211-0050). > > That alone was news to me. But the bigger story is that this is not a > Schuco-specific defect. The polyamide backsheet failure mode is > industry-wide for the 2010 to 2014 era. DuPont's 2019 field reliability > study estimated 12 GW of field failures from PA backsheet through-cracks. > Schuco is unusual in that they actually published a recall. Most of the > other affected manufacturers either went out of business (Solon, Scheuten, > Conergy, Suntech) or quietly handle replacements case-by-case without > public notification. Trina, Yingli, early Canadian Solar, Jinko, Renesola > all show up in field failure literature for this era. > > Why I'm posting: > > 1. We've installed a few of these brands in that window ourselves. I'm now > building an outreach list to proactively notify those clients. I'd be > surprised if I'm the only one in this group with legacy 2010 to 2014 > systems that warrant a second look. > > 2. Symptom that prompted me to dig deeper: we've had multiple clients this > winter reporting intermittent DC ground faults, mostly in cold/wet > conditions, that clear up in dry weather. Classic signature of insulation > breakdown in cracked PA backsheets. Insulation resistance drops with > moisture, recovers when dry. If you're seeing winter-correlated GFDI events > on legacy systems, this is worth checking before chalking it up to age. > > 3. Field protocol matters. Treat suspect arrays as energized regardless of > inverter state. Insulated gloves, photograph nameplates and serial numbers, > and document backsheet condition. Visual cues: chalky white residue, fine > cracks between cells, yellowing, powdery feel when wiped. > > 4. For confirmed-recall modules (Schuco MPE in the affected serial range): > do not reinstall. Manufacturer guidance is to uninstall and dispose. For > other PA-backsheet modules without a formal recall, treat the decision as > an engineering judgment call. Visual inspection (chalking, cracking, > yellowing) plus insulation resistance testing should be your minimum bar > before considering reuse. My personal bias is heavily against reinstalling > any 10+ year old PA-backsheet module given the cost of labor vs. the risk > profile, but that's a business call, not a safety mandate. > > References for anyone who wants to dig in further: > > - Schuco product warning (2022): solarpowerportal.co.uk article "Sch?co > issues product warning over potential defect in solar modules" > - pv-magazine coverage of the expanded warning (Nov 2022) > - UK Gov product safety alert 2211-0050 > - DuPont 2019 Global Field Reliability Study (12 GW failure estimate) > - ScienceDirect, Eder et al, "Error analysis of aged modules with cracked > polyamide backsheets" (2019) > > I searched the list archive and didn't see this come up before. If I missed > an earlier thread, apologies for the duplication. Otherwise, I'm curious > whether others are seeing the winter ground fault pattern, and how folks > are handling client communication and remediation scoping on these legacy > systems. > > > > -- > Nicholas Ponzio > Building Energy > Williston, VT 05495 > http://www.BuildingEnergyVT.com <http://www.buildingenergyvt.com/> -- Zeke Yewdall PV Engineer NABCEP #031508-89 [email protected] 303-523-3592
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