If you’ve spent any time in the solar industry, you probably know that photovoltaic (PV) panels get a lot of attention when it comes to maintenance, efficiency, and troubleshooting. But when I started working as a supplier of other PV accessories—parts that don’t make the headlines, but keep entire solar systems running smoothly—I began noticing a gap: most discussions about self-diagnostics in PV tech focus on inverters or panels, and very few people ask, “What about all the other accessories? Do they have a self-diagnostic function, and does that even matter?” Other Photovoltaic Accessories
At our company, we’ve spent years supplying a range of PV accessories: string combiners, junction boxes, cable connectors, surge protectors, and thermal management components. For a long time, many in the industry viewed these parts as “simple” or “low-stakes” compared to panels and inverters. But over the past five years, we’ve seen a shift. Installers and system operators started coming back to us with questions about why their systems were underperforming, only to trace the issue back to a faulty connector or a misaligned surge protector. That’s when we realized: self-diagnostic functionality for these “secondary” accessories isn’t a nice-to-have—it’s a game-changer.
Let’s start with the basics. What does self-diagnostic function mean for PV accessories, exactly? For most people, the term brings to mind inverters that monitor grid connection voltage or panels that track cell efficiency. But for a PV accessory, self-diagnostics are built-in sensors and software that let the part check its own performance, detect faults, and alert operators before a small issue becomes a major system failure. This isn’t about replacing inverter or panel monitoring—it’s about filling in blind spots.
Take cable connectors, for example. Connectors are the most frequently replaced PV accessory, according to data from the International Electrotechnical Commission (IEC)’s 2023 report on PV system reliability. When connectors get loose, corroded, or damaged, they cause “hot spots” or increased resistance that can drop a system’s overall output by 5-10%—and in extreme cases, start fires. Until recently, connectors had no way to report this. A worker would have to climb a ladder, pull apart strings, and test each connector individually. Now, many advanced connectors on the market include built-in temperature sensors and continuity testers that send real-time data to the system’s monitoring platform. If a connector’s temperature rises 10°C above the system’s average, it triggers an alert. That’s self-diagnosis in action.
Another accessory where self-diagnostics are making a big impact is string combiners. String combiners are the central hubs that group multiple PV panels into one string, directing power to the inverter. A single faulty breaker or diode in a combiner can shut down an entire string of panels, and if the fault isn’t caught early, it can damage the inverter itself. Traditional combiners relied on inverter alerts that could take days to show up, and they often didn’t specify which combiner was the issue. Modern combiners, though, include overcurrent sensors, insulation resistance testers, and even arc fault detection. These sensors run a self-check every few minutes, logging data on each breaker and diode. If a breaker trips or insulation wears down, the combiner sends a specific alert to the operator, identifying exactly which component needs attention. We’ve heard from several installers who reduced their annual service calls for combiner-related issues by 60% after switching to accessories with self-diagnostic features.
Surge protection devices (SPDs) are another area where self-diagnostics matter. PV systems are exposed to lightning strikes and power surges from the grid, and SPDs are designed to absorb excess voltage to protect panels and inverters. But SPDs have a limited lifespan—usually 5-7 years—and once they fail, they can stop working without any obvious signs. A failed SPD means no protection during a storm, which can cost tens of thousands of dollars in damage. Until the last decade, SPDs had no way to alert operators when they needed replacement. Now, most SPDs include a thermal sensor that monitors for internal damage, as well as a status indicator (either on the device or via wireless communication) that shows whether the unit is functional. Some even log the number of surges they’ve absorbed, so operators can plan replacements before the SPD reaches its limit. This is critical for utility-scale solar farms, where a single storm can generate 10+ surges that push an SPD past its capacity.
Of course, it’s not all perfect. There are still many standard PV accessories on the market that don’t have self-diagnostic functions—including some basic junction boxes, low-voltage cable connectors, and even older-style fuses. Why is that? For one thing, cost. Adding sensors, wireless transmitters, and software increases the price of accessories, and many small-scale installers or residential system owners are reluctant to pay the premium. There’s also a lack of industry standards. Right now, there’s no universal IEC or Underwriters Laboratories (UL) standard that defines what “self-diagnostic functionality” means for PV accessories, or how that data should be reported. That means some self-diagnostic accessories only send basic alerts, while others provide detailed performance data, and there’s no way for operators to easily compare them.
But here’s the thing: as PV systems get larger and more integrated into global energy grids, the demand for self-diagnostic accessories is only going to grow. Utility-scale solar farms, which can have hundreds of thousands of individual accessories, rely on remote monitoring to cut down on maintenance costs. If a technician has to drive 200 miles to a farm only to find a faulty connector, that’s a waste of time and money. Self-diagnostic accessories eliminate that guesswork. For residential systems, the ability to get an alert on a phone when a cable connector is overheating gives homeowners peace of mind, knowing their system is safe and efficient.
From our perspective as a supplier, we’ve had to adapt to this shift. A few years ago, most of our orders were for standard, non-diagnostic accessories. Now, nearly 70% of the requests we get are for parts with built-in self-diagnostic features. We’ve worked with manufacturers to develop our own line of diagnostic string combiners and connectors, and we’ve trained our team to help customers understand which accessories will work best for their specific system. For example, a residential installer might not need a top-of-the-line diagnostic combiner, but a utility farm will prioritize that feature to minimize downtime.
One common misconception we still hear is that self-diagnostic accessories are less reliable because they have more moving parts. But data from the U.S. Department of Energy’s 2022 Solar Technologies Office report contradicts that. The study found that PV accessories with integrated self-diagnostics had a 25% lower failure rate than traditional accessories, because the sensors catch issues before they cause permanent damage. The key, though, is choosing accessories where the self-diagnostic system is integrated with the part’s core function—not an afterthought. A connector that adds a sensor without compromising its seal or current-carrying capacity is far more reliable than a basic connector with a sensor glued on.
Another point to consider is data interoperability. Most self-diagnostic accessories generate data, but it’s useless if it can’t be integrated with a system’s existing monitoring software. At our company, we make sure all our diagnostic accessories are compatible with the most common PV monitoring platforms, including SolarEdge, Fronius, and SMA. That way, operators don’t have to invest in new software to use our parts. We also provide simple dashboards that let small-scale users see their accessory performance without needing advanced technical skills.
Looking ahead, the future of PV accessories will be even more connected. We’re already seeing accessories that use artificial intelligence to analyze their own performance data, predicting when a fault will occur before it even happens. For example, a cable connector might notice a gradual increase in resistance over time, and alert the operator that it will need replacement in three months—instead of just reporting a failure when it happens. This predictive maintenance is going to revolutionize how PV systems are maintained, reducing costs and increasing efficiency even further.
But here’s what we want to make clear: even if you have a fully monitored PV system, don’t overlook the accessories. Panels and inverters are important, but the parts that connect and protect them are where most issues start. If you’re still using traditional accessories without self-diagnostics, you might be leaving your system vulnerable to avoidable downtime or damage.
If you’re an installer, system operator, or project manager who wants to learn more about how self-diagnostic PV accessories can improve your system’s performance and reliability, we’re here to help. We work with projects of all sizes, from small residential installations to large utility-scale farms, and we can help you choose the right accessories for your needs.
Photovoltaic Accessories References
- International Electrotechnical Commission (IEC). (2023). PV System Reliability Report: Secondary Components and Failure Rates. Geneva, Switzerland: IEC Press.
- U.S. Department of Energy Solar Technologies Office. (2022). The Role of Accessories in PV System Efficiency and Safety. Washington, D.C.: U.S. Department of Energy.
- Underwriters Laboratories (UL). (2021). Survey of Self-Diagnostic Features in PV Accessories. Northbrook, IL: UL LLC.
Wuxi Chenglida Machinery Co., Ltd.
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