What is AFCI and why does it matter to your solar PV system?
Did you know that AFCI (Arc Fault Circuit Interrupter) technology can significantly enhance the safety of your solar PV system? Discover how AFCI technology helps boost your solar system safety by preventing dangerous arc faults.
Are your solar panels protected from hidden electrical risks?
Solar photovoltaic (PV) systems operate at high voltages, making them susceptible to what are known as arc faults – dangerous electrical discharges caused by loose connections or damaged insulation.
These faults can often lead to more serious problems such as overheating, damage to your system, and in the worst cases, fires.
That’s where Arc-Fault Circuit Interrupters (AFCIs) come into play.
Designed to detect and stop arc faults before they cause harm, AFCI technology has become an essential safety measure for any modern solar PV system.
Let’s take a further look at what AFCIs are, why they’re such an important part of protecting your solar setup, and how Hoymiles’ innovative microinverters are setting new standards for safety and compliance.
What is an AFCI?
Arc-Fault Circuit Interrupters (AFCIs) are safety devices designed to detect and stop arc faults – which as we mentioned earlier are dangerous electrical discharges that can happen when a circuit is damaged or connections are loose.
By cutting off the flow of electricity at the very first sign of trouble, AFCIs help prevent these faults from escalating into far more dangerous events such as overheating, fires, or system failures.
What is an arc fault?
In a regular PV system, the DC side voltage can be as high as 600-1000V. Any loose connection between PV module connectors, poor contact in the circuits, damp wires, or damaged insulation can easily cause a DC arc fault.
The temperature at the point of contact can rise up to 3000-7000℃, which will carbonize the surrounding components. This leads to fusing and cable damage at best, and may burn up modules, devices, and even cause fires at worst.
In solar PV systems, arc faults can burn much hotter and longer than in standard electrical systems. This, of course, makes them far more hazardous than your standard circuit.
Fires at traditional PV stations cannot be directly put out with water because of the high DC voltage, so installing PV inverters that are equipped with the arc fault detection function is a must.
What is an AFCI circuit breaker and how does it work?
An AFCI circuit breaker is a unit designed to detect the unique electrical patterns most commonly associated with arc faults.
They monitor your system’s electrical flow and pick up on the telltale fluctuations that signal there could be a problem.
Once an issue is detected, the breaker automatically shuts down the affected circuit, stopping the arc in its tracks and significantly minimizing the risk of fire or damage.
Why is an AFCI important for your solar safety?
Solar PV systems are designed to generate clean, reliable energy.
Sounds perfect, right?
But there is one downside – their high-voltage DC circuits can pose unique safety challenges that can be challenging to tackle.
Without the right safeguards in place, these systems can be vulnerable to arc faults and the dangers they bring.
Here’s why having AFCI protection is a must-have for solar safety:
- Helps prevent fire hazards: Did you know that arc faults can reach temperatures of over 5,432°F (3000°C)? This makes them the leading causeof electrical fires in solar installations. AFCIs can detect these faults early, cutting off the circuit and preventing sparks from escalating into fires.
- Protects your investment: An arc fault can lead to damage to expensive PV components, from the wiring to the panels themselves. AFCI protection helps to keep the longevity of your system by stopping faults before they cause irreparable, expensive damage.
- Keeps you compliant with regulations: AFCI technology is now a mandatory requirement in many countries, including Brazil and the United States. Without AFCI protection, systems can fail inspections or risk non-compliance with safety codes.
- Gives you peace of mind: Knowing your system has that extra layer of safety means you can enjoy the benefits of clean energy without worrying about any hidden risks.
How to protect your solar system from arc faults
It’s absolutely essential to put measures in place to protect your solar system from arc faults.
Of course, there’s no way to completely eliminate the risks, but choosing the right technology can significantly cut down on any danger and help you maintain safety and reliability.
Here are three common solutions:
String inverter + AFCI
String inverters combined with AFCI devices can detect and interrupt arc faults.
However, they operate at high DC voltages, which can make shutdowns more complex and even potentially hazardous.
While they do a great job when it comes to arc suppression, they also lack module-level shutdown capabilities, which unfortunately somewhat limits their overall safety profile.
String inverter + RSD
Adding a Rapid Shutdown Device (RSD) to a string inverter boosts protection by lowering the DC voltage after shutdown.
This system gives you both arc suppression and module-level shutdown, which offers an extra layer of safety compared to using just a lone string inverter.
Microinverter
Microinverters are the most safety-focused option of the three. They take things to the next level by operating at low DC voltages during normal use and after shutdown.
They also offer module-level shutdown capabilities, which gives them the edge when it comes to protecting against arc faults. Plus, their low-voltage design inherently reduces the risks normally associated with high-voltage arcs.
Why are microinverters naturally AFCI-compliant?
When it comes to safety, microinverters stand out as a naturally AFCI-compliant solution.
Their design addresses many of the risks normally associated with traditional solar setups, particularly arc faults.
Low DC voltage for maximum safety
Unlike string inverters, which operate at high DC voltage across long circuits, microinverters work at much lower voltages – typically below 60 V.
This helps to significantly reduce the chance of dangerous arc faults occurring. And even if one were to arise, the lower voltage makes it far easier to manage and contain.
Module-level arc extinguishing for added protection
Microinverters are installed at the module level – which means each panel has its own dedicated inverter. This setup means that you can do a module-level extinguishing, which stamps out individual panels’ arc faults once any risk is detected.
This allows you to protect the rest of your system and gives you the ability to carry out maintenance and emergency responses safely and efficiently.
What are AFCI regulations across the world?
As solar energy adoption continues to grow around the globe, so does the need for standardized safety regulations.
Brazil
In December 2024, Brazil’s National Institute of Metrology, Quality, and Technology (Inmetro) introduced new AFCI regulations.
These rules mandate that all solar inverters operating at any DC voltage higher than 120 V have to include AFCI protection to prevent fires caused by arc faults. Solar inverters without AFCIs were still allowed until the end of 2024, but from 2025 onwards, compliance is mandatory for certification and safety inspections.
Hoymiles has already aligned with these regulations. Our AFCI-compliant microinverters passed rigorous certification tests according to IEC 63027 standards.
By offering low-voltage, module-level shutdown, and integrated arc suppression, Hoymiles microinverters set the benchmark for safety and compliance in Brazil.
The United States
In the U.S., the National Electric Code (NEC) has required AFCI protection for solar PV systems with DC circuits over 80 V since 2011 (NEC 2023 690.11).
This regulation mandates that all systems installed in or on a building must include measures to detect and interrupt arc faults.
Systems must disable affected circuits and require a manual restart after a fault is detected.
As Hoymiles’ microinverters operate at below 60 V DC, they are automatically AFCI-safe in the United States.
Safer, smarter solar systems
Arc faults are a serious safety risk for any solar PV system, but they don’t have to be.
By understanding the importance of AFCI technology and choosing the right protection measures, you can safeguard your investment, comply with global regulations, and enjoy the peace of mind that comes with knowing your system is built for safety.
Hoymiles’ microinverters offer a naturally AFCI-compliant solution. With their low DC voltage, module-level shutdown capabilities, and advanced arc suppression features, they are the smart choice for any PV system.
Ready to make your solar system safer and smarter?
Explore Hoymiles’ microinverter solutions and take the next step in protecting your solar energy future.
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