here for the sunshine shenanigans
We’ll sometimes get the question, “Can I use Enphase with UL 3741,” or “why isn’t SolarEdge listed on your website?”
They are perfectly good questions — SolarEdge themselves have touted being the first to UL 3741 compliance, since they were listed via Intertek in 2021, and Enphase got certified by UL around the same time. Just recently in May of 2025, Generac listed their inverter to UL 3741 compliance through Intertek. So why aren’t these inverters or systems listed on the website?
There are now dozens of solar structures, commonly referred to as racking, that are listed as PV Hazard Control Systems (PVHCS) under UL 3741. As time goes on, we’re seeing some differences in how listing bodies allow structures to be listed.
Let’s talk about what all has developed in UL 3741 news this summer! It was a lil bit crazy and a lot of fun.
A ton of news around a bunch of companies, including Tesla, Unirac, Solis, Ironridge, MidNite Solar, Pegasus, TerraGen, EZ Solar, and more!
Make sure to check out https://ul3741.com to stay updated on UL 3741 news and product compatibility.
Talked with TJ from SMA America about their upcoming 3-in-1 rapid shutdown device at RE+ this year!
The SMA Smart Shutdown is a 3-in-1 device (1 SSS can shut down 3 panels), and is RAIL-mounted, not panel mounted. Could be a pretty great option. It’s not string shutdown yet, but design-wise, the install process looks to be better than any other rapid shutdown device I’ve seen out there so far.
SMA says the SMA Smart Shutdown is coming in Q2 of 2025, along with their larger Sunny Boy Smart Energy and Home Storage products.
Editor’s note 07/09/24 – An earlier version of this article asserted that any module could be used with the Pegasus railing. That was incorrect, and the offending intern has been sacked.
Amid Unirac publishing their new listings for NXT Umount and SolarMount, and rumor of EcoFasten getting their railings listed, Pegasus may have just completely blown the roof off the expectations for 3741 listings.
To date, the onus of testing has been placed on the racking manufacturer, who gathers all the ingredients, in dozens of permutations, to test components like modules, inverters, and MLPE. All those components are then specifically listed in the racking manufacturer’s “3741 installation addendum”, or some other document that modifies the installation manual for 3741 applications.
However, Pegasus contacted me this week to show me their listing: one with ZERO approved inverter vendors lists. No inverters, no MLPE. Excuse me, but what in the actual fuck.
I initially assumed that there was a document they forgot to send, so of course I asked for a list of approved vendors. They wrote back that no, there was no mistake. They simply don’t have a list of approved vendors, and that as long as the equipment used is listed under UL 1741 (or has some other specific UL 3741 COC), you may use that equipment with their railing.
ANY inverter. Not just an inverter that’s been tested by some other racking manufacturer, but ANY inverter. The implication is that literally everyone else could do this, too. We could find ourselves in a situation where picking an inverter and rail system that works with UL 3741 will no longer feel like untying a Gordian knot; instead, we’ll be slicing through it with a sword.
I have so many feelings about this— a mix of excitement, frustration, and dread. I’m excited that this indicates the industry could move to a much simpler way of listing these products, spending less of humanity’s time on confusion, lowering the barrier to entry, and allowing for more solar that is less complex. I’m frustrated that only now, 2 years after the first listing with SMA and Sollega, have we discovered that this is possible. And I’m dreading that the code body will see this, say “Oh, you’re not supposed to be able to do that”, and change the standard to lock out this option.
There’s probably good reasons why racking companies have defaulted to listing every piece of third party equipment, but it seems to be an overly large burden. It also ends up being far more complicated for the end user than it should be. Even if Pegasus’ strategy isn’t technically correct in some way, I hope we can compensate by adding the appropriate requirements into inverter listings, instead of overstuffing racking listings with redundancy.
Truly, the biggest obstacle to greater UL 3741 implementation is confusion about what equipment can be used (and also SolarEdge/Bill Brooks trying to undercut it and scare everyone with any chance they get). This is the entire reason I created UL3741.com, and dear reader, I truly hope this action by Pegasus will lead to the website’s demise. Simplifying the listing like Pegasus has done is the coolest thing ever. I just hope that we get to keep it.
Looks like for residential, we’re still stuck with Tesla as the inverter solution. Hoping we get some other manufacturers in the mix, soon.
I imagine I may have been the subject of some colorful language today. 😅 I don’t see any manuals up yet, so I’d guess we’ll see them tomorrow or later in the week. I’ll get all the details posted on UL3741.com as soon as I get those in my sunny li’l hands.
Intertek has posted the updated Photovoltaic Hazard Control listings for Unirac on their directory, and it includes a few new racking models.
Included in the listing are existing racking models, which are exclusive to flat roof solutions, but newly added to the list are NXT Umount and SolarMount, with callouts for both residential and commercial.
The full list of new addendums:
We don’t know yet what inverters will be listed with these racking systems, or exactly what installation will look like, but it’s safe to assume that we can expect something similar to Ironridge and Chiko’s listings.
Chiko is the only company so far to have listings for a sloped-roof racking that includes commercial inverters, but it sounds like Unirac will be next to the party. This will be immensely helpful for solutions like agriculture, where there’s often large, accessible, sloped roofs that could accommodate roof-mounted inverters.
This is as yet unannounced by Unirac, so the cited documentation in the listing is not available publicly. I imagine we’ll see more details in the coming weeks. Update: Unirac has now officially announced these listings.
If you want to know the details of the yet-to-be-released documents once they’re available, make sure to subscribe to the newsletter at UL3741.com. While you’re there, you can explore all current UL 3741 listings, cross-referenced with compatible inverters and array-level rapid-shutdown systems.
Announcement! Are you having a hard time tracking down what inverters and racking systems are compatible with UL 3741? I’ve made a website for that!
https://ul3741.com/
This is a passion project of mine, to categorize all inverters and racking systems that are listed with UL 3741, on a website that’s accessible and easy to navigate. I know of a couple things I still need to add to the site, but it’s pretty fleshed out already, and I’d appreciate feedback on what’s helpful and what you think it still needs.
If you’re a brand and feel like your products aren’t represented properly, please feel free to reach out using the contact form on the website so we can get things straightened out. I want this to be beneficial to both consumers and manufacturers.
Big thanks to John Weaver (aka Commercial Solar Guy) for inspiring this idea!
Thanks to Sean White for asking me on to talk about the industry and UL 3741! It was great fun.
This one’s been a long time coming. But maybe we can FINALLY ditch module level power electronics in standard solar installations!
If you missed the news, here’s Ironridge’s press release about getting their flush mount racking and Tesla equipment listed with UL 3741.