connectors Archives - Sun Pull Wire

Utility-scale solar installations have a lot of fragile parts and pieces. Small issues can result in thousands of dollars’ worth of lost energy, system damage, or even a fire.

According to HelioVolta’s SolarGrade PV Health Report, nearly 60% of solar installation issues were attributed to field-made connectors or wire management. Field-made connector issues alone attributed to one-third of all problems at solar sites. Within that segment, the percentage of critical and major issues attributed to field-made connectors was higher than any other damage type.

It’s fair to say connectors are a concern, but it helps to know when and how the connectors were made. Field-made connectors are installed on-site by workers, compared to factory-made ones attached to PV wire during production.

With that in mind, the blame then falls on either the connector or the worker who assembled it.

With so much money and energy on the line, companies must reduce liability and increase their installations’ reliability. Could factory-made connectors improve overall production and dependability?

The Difference Between Field and Factory-Made Solar Connectors

Companies have two options for connectors for a utility-scale solar power array: factory-made connectors or field-made solar connectors.

Factory-made connectors are installed onto the wire in a controlled environment. Performing the work in a manufacturing facility makes it easier to spot quality assurance (QA) and quality control (QC) issues so bad connectors aren’t sent out to the field.

When PV wire connectors are made in the field, they’re assembled by solar installers. Typically, field-made connectors are used to ensure connectors aren’t cross-mated with other “compatible” parts. During this process, workers use certified pieces and tools supplied by a manufacturer and then do the work themselves. The important thing to remember here is that both the parts and the tools are certified, meaning installers should only use what was supplied to them by the manufacturer.

Although several connector types exist on the market, some are more common than others. MC4 connectors, using a plug-and-socket method, are the current standard, and Swiss manufacturer Staubli is the original developer and manufacturer. Since the MC4’s inception, many other companies have started making their own compatible connectors, leading to a growing number of connector manufacturers and parts to choose from.

The problem is although there is a certification process for the connectors, cross-mated parts aren’t usually tested together as a single unit.

One Size Doesn’t Fit All

There are several types of connectors used in solar operations, including the MC4, MC3 (phased out by MC4), and Amphenol Helios models, but you can’t always use one with another.

While it might not seem like a big deal mixing and matching connectors across a solar site, HelioVolta noted in its SolarGrade report that pieces were either improperly installed or cross-mated in nearly 80% of field-made connector issues.

As installers rush to catch up with delayed projects and set up new sites, the resulting time crunch opens the door for mistakes. The industry is also growing, leading to an influx of junior installers who may not have enough experience to perform the job well.

What Does This Mean for Solar Sites?

Connector issues set the stage for several problems. From water and moisture exposure, bad PV connector points, and damaged wires from bad crimps or other mistakes, every issue could open the door to a costly disaster.

So, what happens when a PV system has connector issues? Quite a lot, actually:

Lost power and outages – When connectors fail, the solar panel is no longer reliably connected to the Balance of System (BOS). When that happens, the system produces less energy.
Ground faults or arcing – Ground faults and arcs occur when there isn’t good contact in the connector. Heat expands the parts over time, opening gaps and eventually creating an arc that can damage surrounding wires and materials.
Fires – When fires break out, they can quickly cause millions of dollars in damage. Once the fire is out, crews need to replace damaged and charred parts, adding sunk time and labor costs to the total bill.

Not every field-made connector is an inherent fire risk, but they may carry more risk than factory-made parts, according to HelioVolta’s data.

Avoiding Connector Issues

Limiting the number of fail points is critical when dealing with large utility-scale installations.

Buying factory-made connectors addresses a crucial failure point, setting your solar energy project up for better long-term success.

According to the SolarGrade PV Health Report, only 6% of issues at solar arrays were tied to factory-made connectors, much less than the 33% associated with their field-made counterparts. Manufacturer-made parts also reduce on-site critical and major problems, thanks to each manufacturer’s rigorous QC and QA programs.

The Best Connector for the Wire

Another benefit of factory-made connectors is that manufacturers can use compatible products with their wire and cable. The result is a more reliable connection, thanks to a standardized process retaining integrity across the board.

Installers may rush or get stretched thin, limiting their attention, resulting in potentially loose or poor connections. Furthermore, unlike field-made connectors that may lack QA assurance from another worker in the field, most manufacturers have staff on hand to spot potential concerns before the wire leaves the factory.

What Do Bad Connectors Look Like?

No matter what type of connector is used, you should know what damage looks like.

We recommend having crews inspect solar sites once every 6 months or so and check every connection point for common problems, including:

Gaps
Cross-threading
Sun Damage
Overheating
Other connector or wire damage

One of the easiest mistakes to make is using incompatible connectors. When connectors are cross-mated without checking for compatibility, it can put the solar installation at risk. Mismatched connections can generate a lot of heat, making them easy to spot with a temperature gauge.

It’s also important to ensure every installer is trained to properly work on solar panels, cabling and other balance of system (BOS) pieces.

Know What You’re Getting

Simply put – buying factory-made connectors reduces risk.

Manufacturers have strict quality control standards to prevent damaged or improperly assembled connectors from being shipped out to the field in the first place. If bad parts do get shipped, they can also work alongside customers to quickly correct mistakes before dangerous situations develop.

Not all field-made connectors will have issues, and many will be fine. But when the goal is to limit risk and liability on your renewable energy project, factory-made connectors are the way to go.

Installation costs, labor, and product reliability often go together when bringing utility-scale solar projects online.

Despite declining hard and soft costs, there is still pressure to deliver projects on time and under budget. This means installers look for every way to save time and money.

Material and labor costs usually provide some savings, but the solutions aren’t always elegant. One issue creeping into the solar conversation is the reliability of PV wire connectors and harnesses that cut down on labor but increase the number of fail points in the balance of system (BOS).

When crews use harnesses, it means more connectors to bring wires together. More connections generally mean more opportunities for issues. Whether it’s installation related, tied to the weather, or just a random event, solar panels can’t do their job if connectors break.

By limiting the number of PV cable connectors, installers reduce the number of fail points and increase reliability.

Why Companies Use Connectors

Every solar project will require MC4 connectors, but the number needed depends on how the installer approaches the problem.

When companies use Sun-Pull bundled PV wire, it’s a 1:1 connection. This means one wire, one string, and one connector from the solar panel to the combiner box. Although the bundle has individual #10 AWG conductors, they can be terminated at different points along the run. As a result, workers only have to move down the line once.

If a company decides to increase the number of connectors used, it would need about half the amount of wire compared to a bundled cable solution. They could also use a larger gauge wire (in this case, #8 AWG) than the #10 AWG used in the bundled wire, reducing electricity lost from the solar panel to the combiner box.

Using connectors across the solar array sounds like a slam dunk, but several drawbacks complicate matters.

No Real Cost Savings

Although the installer needs about half the wire, the larger gauge wire eats into the cost savings. Not to mention, the project now requires harnesses and additional connectors to complete the job. All told, the savings are nearly negligible.

The company might find labor cost savings, which are reduced since workers are installing less wire. Using more connectors saves labor hours, but crews still need to take multiple trips down the line.

“It’s a less elegant method,” Sun-Pull Wire President Nick Eberly explained. “It will cut your labor in half, you only have to go down that row half the number of times because you’re installing a harness, but you’re installing double the number of connectors. You’re also still going down the row multiple times, compared to a bundled wire which requires going down the line once.”

More Connections, More Failure Points

It might not seem like a big deal, but too many connectors can cripple solar installations.

If you’ve ever left something plastic outside, you’ve likely seen firsthand what the elements do to it over time. The same can be said about the plastic housing connectors have that protect the pins and sockets inside.

When joining PV panels to the combiner box, the plastic connector pieces are exposed to the elements, eventually degrading them. Although they’re sunlight resistant, they’re still vulnerable to excess moisture, snow, and other environmental factors. If water sneaks into the connector, it can create a short.

“If you have a piece of wire that’s insulated, that can stay outside for a really long time in the elements,” Eberly explained. “Wherever you put that connector, that’s generally going to fail quicker than the wire itself. And every time one of those connectors blows, a fuse blows too. That lowers the output, and then you have to fix that.”

Eberly suggests a single conductor approach that eliminates as many connectors as possible. In this scenario, a wire runs from the solar panel to the combiner box, keeping sensitive pieces safe while limiting exposure.

It’s Not Always the Connector’s Fault

Sometimes connectors fail through no fault of their own – they get a little help from some unlikely sources.

The products widely used today are called MC4 connectors and were developed by Staubli, a Swiss manufacturer. Although the company owns about one-third of the product’s global market share, hundreds of global connector manufacturers exist, mostly in Asia. Unfortunately, there isn’t a universal standard, meaning manufacturers can produce similar products with subtle differences that could impact performance.

Beyond manufacturing, installers may cause connector failures. From putting connectors on backward and not crimping them hard enough to crimping the surrounding wire insulation, cross-threading, or under/over-torquing them, problems can occur.

As a result, issues could range from a loss of electrical output and performance to full-blown fires.

According to a 2019 Fraunhofer Institute for Solar Energy Systems report, many connector failures found on utility-scale solar arrays happen within the first five years. Additionally, a joint study by PVEL and HelioVolta found connector issues in more than 70% of commercial and industrial projects analyzed by HelioVolta.

With so many variations on the market, it’s difficult to ensure quality, leading to potential delays and setbacks. And when harnesses are used, connector failures often mean the whole harness needs to be replaced.

Small Parts, Huge Impact

Connectors may not seem like a big deal, but there’s a cascading effect whenever one fails.

Let’s say a connector fails at a large solar project. The system loses output because of the damaged connector, and the piece could create a situation where arcs, sparks, or fire occur.

When that happens, the utility or company has to pay labor costs for workers to go out and fix the damage and material costs for a new connector, PV wire, and other BOS parts. The company also loses money because the system isn’t generating as much power, leading to lower profits and potentially unhappy customers.

This isn’t to say every connector failure will cost hundreds of thousands of dollars to repair. But when multiple connectors fail on a large site, several tiny problems can become a giant headache.

One (String) and Done

There isn’t one way to wire a utility-scale solar power site, but it’s possible to save time, labor, and money by finding a system that works well for you.

Bundled PV wire is a simple solution that reduces fail points from the solar panels to the combiner box and lets workers travel each row once. There’s also no need for harnesses or multiple connection points to connect wires. It’s a safer, more reliable system with less risk of failures, such as electrical arcing or dangerous contact with DC electricity.

Like other types of renewable energy, solar is on the rise. Of course, work must be done to fully standardize the process, but the necessary steps are taking place. According to PVEL, the NEC was revised in 2020 to require connector pairs to be tested and certified for intermateability. It’s one small step toward a universal process in the United States.

Connectors are only one piece of a solar BOS, but they’re a potential weak point. Finding solutions that need fewer parts and are more reliable makes it easier to save money on future projects and speeds up the nation’s move away from fossil fuels.

Tag: connectors

Factory vs. Field-Made: Comparing Solar Connectors