Fonrich Arc Protection Box: The "Safety Core" for Industrial & Commercial Rooftop PV Plants

Industrial and commercial rooftop PV plants operate at full load daily, and their greatest fear is fire—with arc faults being the top "culprit." Fortunately, the Fonrich FR-AFCI-B04A Arc Protection Box is specifically designed to address this pain point. It excels at precise arc extinguishing, adapting to complex rooftop environments, and enabling intelligent operation and maintenance, making it the "safety core" of industrial rooftop plants and ensuring stable power generation for PV systems.

I. Three Core Protections: Safeguarding Rooftop Safety from Arc Extinguishing to Personnel Protection

Commercial rooftop plants are most afraid of "chain reactions caused by arcs." The FR-AFCI-B04A targets three key areas—"arc extinguishing, asset protection, and personnel safety"—to eliminate risks at the source:

1. Proactive Arc Extinguishing: Millisecond-Level Shutdown to Stop Arc Propagation

It monitors arc signals in the circuit 24/7. Whether it is a "series arc" caused by aging wires or a "parallel arc" due to loose connectors, once detected, the faulty circuit is shut down in as fast as milliseconds—faster than a human blink. There is simply no time for the arc to ignite or spread.

2. Asset Protection: Preventing Million-Level Losses to Safeguard the Plant’s "Finances"

The modules, inverters, and cables of industrial/commercial rooftop plants cost millions of baht in total. If an arc triggers a fire, not only will all equipment be ruined, but the rooftop factory building may also suffer damage. The FR-AFCI-B04A acts like "insurance" for these assets: it eliminates arc-induced fires at the source, sparing the plant from the risk of "catastrophic losses in case of ignition."

3. Personnel Safety: Eliminating High-Voltage Hazards for Peace of Mind During Operations

During plant operation and maintenance, technicians must work near string arrays and combiner boxes. Hidden arcs pose a high-voltage danger that could harm personnel. After the FR-AFCI-B04A shuts down a faulty circuit, it reduces the voltage in the faulty path to a safe level. Even when technicians approach to inspect, there is no risk of electric shock—fundamentally ensuring operational safety.

II. "All-Round Adaptation" to Complex Environments: Suitable for New/Old Plants & Any Rooftop Structure

Industrial rooftops present complex scenarios: some are new steel-structured rooftops, while others are old concrete rooftops used for over a decade; some use inverters of Brand A, others Brand B; rooftop temperatures can reach 60℃ in summer and drop below 0℃ in winter. The FR-AFCI-B04A is fully adaptable to these conditions:

1. Multi-Equipment Compatibility: Installable in New & Old Plants, No Inverter Replacement Needed

It is directly compatible with mainstream string inverters (e.g., Huawei, Sungrow, GoodWe) used in new plants, as well as older inverters in existing plants. There is no need to replace equipment specifically to install the protection box.

2. Wide Temperature Range & Multi-Bracket Compatibility: Resistant to Heat/Cold, Suitable for Any Rooftop

It can withstand temperature fluctuations from -25℃ to 60℃—no freezing in northern winters and no performance degradation in southern summers. Additionally, the back of the box has pre-drilled mounting holes, allowing easy installation on angle iron brackets, aluminum alloy brackets, or cement weight brackets. Technicians can install one unit in half a day, with no need for extra drilling or accessories.

III. Three Breakthroughs in Intelligent Protection: Manage via Mobile Phone, Save Maintenance Effort

Industrial plants are large-scale, with dozens or even hundreds of strings—manual monitoring alone is unmanageable. The FR-AFCI-B04A’s intelligent design transforms maintenance from "on-site trips" to "mobile phone operations," multiplying efficiency:

1. One-Click Protection Mode Switch: Accurate Response to Different Scenarios

No on-site parameter adjustments are needed—modes can be switched with a tap on the mobile APP, ensuring accuracy and convenience for different scenarios:

• Standard Mode: Used during normal operation. Monitors arcs in real time and shuts down automatically if issues occur, without disrupting normal power generation.

• Anti-Interference Mode: Enhances protection sensitivity during severe weather (e.g., typhoons, heavy rains). It avoids blind tripping even if current fluctuates slightly and enables rapid power restoration.

• Custom Mode: Used for plants with special equipment (e.g., energy storage). Allows users to set arc extinguishing thresholds, recovery times, and frequencies to meet specific requirements.

2. Four-Circuit Independent Protection: Faulty Strings Don’t Affect Others, Minimizing Power Loss

It supports a maximum system voltage of 1100V and a system current of 20A, capable of protecting 4 PV strings simultaneously with "independent protection." If one string malfunctions, only that string’s power is cut off, while the other three continue generating electricity—minimizing power loss. A garment factory’s plant tested this: String 2 developed an arc due to insulation damage, and the protection box only shut down String 2. The other three strings generated an extra 800 kWh that day—avoiding the significant loss that would have occurred if the entire inverter had been shut down. Additionally, the device’s 4-color LED display (red, green, yellow, blue) corresponds to the status of the 4 strings. Technicians can identify faulty strings at a glance on-site, no need for one-by-one testing.

3. Cloud-Connected Operation & Maintenance: Remote Monitoring & Automatic Alerts, No Daily On-Site Visits

Via the cloud platform and mobile APP, users can remotely check the real-time status of each protection box—clearly seeing which strings are operating normally, which are powered off, and how long the outage has lasted. If a string’s arc extinguishing count exceeds the preset threshold, the APP automatically alerts maintenance technicians, preventing fault escalation. More thoughtfully, in case of an abnormal power outage, the device automatically stores fault logs, recording the issue and arc type. This makes later troubleshooting easy, with no need for technicians to rely on memory.

Simple Deployment: Worry-Free for New Plants & Old Plant Retrofits, No Major Overhauls

Whether for new plant installation or old plant retrofitting, the FR-AFCI-B04A requires no "major demolition or modification," making deployment simple:

• No extra wiring: Directly connect to the original string and combiner box lines. Interfaces match mainstream specifications—plug and play.

• No extra accessories: The box comes with built-in installation parts. Whether mounted on rooftop brackets or next to combiner boxes, no additional parts need to be purchased.

• Fast retrofitting: When retrofitting old plants, there is no need to shut down the entire plant. Remove the original general protection device, replace it with the FR-AFCI-B04A, and restore power to one circuit in half an hour—minimal impact on overall generation.

A "Must-Have Safety Requirement" for Industrial & Commercial Rooftop Plants

Today, as industrial rooftop PV plants become more common, the risk of arc faults grows. The FR-AFCI-B04A is not an "optional accessory" but a "must-install safety line." It not only extinguishes arcs in milliseconds to prevent fires but also adapts to complex environments and enables intelligent maintenance. Whether for new or old plants, installing it safeguards equipment and factories, reduces power loss, and ensures every kilowatt of green electricity is generated safely and reliably.