AFCI Circuit Breakers in PV: Key Applications and Benefits

Today, the PV industry is booming, but one hidden risk is more worrying than anything else—arc faults! This hazard is usually hard to detect, but once it occurs, its ultra-high temperature can ignite wire insulation and thermal insulation cotton within minutes, not only damaging equipment but also posing severe threats to human safety. Fortunately, the AFCI (Arc Fault Circuit Interrupter) Circuit Breaker (a dedicated arc protection circuit breaker) has now become a "safety standard" for PV systems. Today, we’ll take a deep dive into where AFCI circuit breakers are used in PV systems and what benefits they offer, helping you understand why they are so crucial.

Where Do Arc Faults Come From?

Most arc faults occur due to aging wires, loose connectors, or damaged insulation. When current deviates from its normal path and "sparks" randomly, it releases extremely high temperatures. If there are flammable materials nearby, a fire will start immediately.

PV systems require extra caution: Equipment like solar panels, inverters, and combiner boxes are used outdoors year-round, exposed to wind, sun, moisture, cold, and dust. Wires and connectors are particularly prone to aging and damage. It is reported that over 80% of PV fires are related to arc faults. Whether it’s a small rooftop PV system or a large power station covering hundreds of acres, once this problem occurs, equipment damage is the least of the concerns—if not detected in time, the losses are incalculable.

How Does an AFCI Circuit Breaker Work? Millisecond-Level Shutdown, No Chance for Flames to Ignite

Unlike ordinary circuit breakers, AFCI circuit breakers continuously monitor current signals in the circuit. They can accurately identify series arcs (e.g., sparks from broken wires), parallel arcs (e.g., sparks from two wires touching), and ground arcs.

Once an arc is detected, it cuts off the current in "milliseconds"—to put this in perspective, it’s faster than a blink of an eye! There is no chance for the arc to spread or ignite nearby objects. In the past, without this device, even if an arc was detected, manual power shutdown would be too late; now, with an AFCI, it’s like installing an "automatic fire-extinguishing switch" for the system, significantly enhancing safety.

Where Are AFCI Circuit Breakers Installed in PV Systems?

AFCI circuit breakers are not installed randomly—they must be matched to the "key parts" of the PV system to fully mitigate risks:

1. Module-Level: Each Panel Gets a "Safety Shield"

The wiring of each solar panel is a "high-frequency area" for arc faults—for example, loose connectors between panels or aging wiring due to long-term exposure. At this level, installing an AFCI circuit breaker for each panel ensures that if an arc occurs in one panel, its power supply can be cut off immediately without affecting adjacent panels. It’s equivalent to equipping each panel with a "personal bodyguard."

2. String-Level: A Fault in One String Won’t Affect Others

Many PV systems connect several panels in a "string." Without an AFCI, if an arc occurs in one panel of a string, the entire string would have to be shut down. Installing an AFCI circuit breaker at the output end of the string only cuts off the faulty string, allowing other normal strings to continue generating power. This avoids reducing the entire power station’s output due to a single minor issue.

3. Inverter-Level: Protecting the System’s "Heart"

The inverter is the "heart" of the PV system, responsible for converting DC power to AC power. If an arc occurs here, the entire system could be paralyzed. Installing an AFCI at the inverter level cuts off the fault current in the first instance, not only protecting the inverter but also preventing the fault from spreading to the grid side, directly meeting safety requirements.

Beyond Fire Prevention: What Other Benefits Do AFCI Circuit Breakers Offer?

1. Reliable Safety Even in Harsh Environments

Whether a PV power station is on a humid rooftop in southern China or a dusty area in northern China, AFCI circuit breakers maintain stable performance. They continuously monitor the circuit; even if equipment aging (caused by the environment) leads to arcs, the AFCI can cut off power promptly. With it, you don’t have to worry about the power station catching fire every day, regardless of high temperatures or rainy weather.

2. Effortless O&M—No More Blind Troubleshooting

Most AFCIs come with intelligent monitoring and transmit real-time data to the backend. If a fault occurs, alerts are sent to your phone. O&M technicians don’t need to inspect panels one by one; they can locate the problem directly based on alerts, saving significant time and labor costs. For example, Fonrich’s AFCI circuit breakers connect to the SafeSolar monitoring platform—you can see at a glance which circuit has an arc and when it occurred, greatly improving O&M efficiency.

3. Compliance with Standards—Smooth Project Approval

Today, many countries and regions have strict requirements for installing AFCIs in PV power stations—such as the NEC standard in the United States and relevant specifications in China. Installing a standard-compliant AFCI (like Fonrich’s, which meets UL 1699B) ensures smooth acceptance for both self-use and grid-connected projects, while also enhancing the project’s market competitiveness.

4. Easy Installation and Maintenance—Suitable for Aged Systems

Installing an AFCI is similar to installing an ordinary circuit breaker—no modifications to the existing system are needed, making it suitable for retrofitting aged power stations. For example, some aged PV systems that have been in operation for 5-6 years can be upgraded with AFCIs; Fonrich’s products are directly compatible with original equipment, and installation takes only half a day, minimizing downtime and avoiding disruption to power generation.

The Future of AFCI: Smarter, with Early "Risk Prediction"

In the future, AFCI circuit breakers will become even more advanced: They will not only "detect faults" but also seamlessly integrate with inverters, combiner boxes, and other equipment to pinpoint exactly which panel or connector is faulty. Combined with IoT technology, they will also process data via cloud platforms to predict potential arc risks in advance—for example, if a connector repeatedly sends abnormal signals, it will alert O&M technicians to conduct proactive maintenance, eliminating risks at the source.

Conclusion: For PV Safety, AFCIs Are Indispensable

In today’s PV industry, safety is always the top priority, and AFCI circuit breakers are the "key line of defense" against arc-induced fires. Whether for new power stations or retrofitting aged ones, choosing a suitable AFCI (like Fonrich’s, which offers strong adaptability, safety certifications, and intelligent monitoring) not only prevents fires and reduces O&M costs but also ensures compliance with standards, keeping the power station running stably. As technology matures, AFCIs will undoubtedly become a "standard essential" for PV systems, paving the way for the safe development of the PV industry.