Arc Faults in Solar Systems: Causes and Solutions for Prevention

The growing prevalence of distributed photovoltaic power plants in industrial, commercial, and residential settings has heightened the significance of safety standards and technologies in photovoltaic solar systems, particularly concerning fire hazards within these facilities. While there are various internal and external factors that can trigger fires in photovoltaic systems, “arc-faults” play a particularly significant role in such incidents. This article aims to delve into arc-faults and explore their impact on photovoltaic system fires.


Safety in solar photovoltaic systems

  The electrical safety design of photovoltaic arrays primarily adheres to the guidelines outlined in IEC 62548, titled “Requirements for the Design of Photovoltaic Arrays.” This standard sets design requirements pertaining to various aspects, including protection against electric shock, overcurrent protection, grounding, residual current monitoring and response, lightning and overvoltage protection, as well as the selection and installation of electrical devices.   The analysis of various incidents has revealed that the existing standards lack comprehensiveness and effectiveness. For instance, the factors influencing the design of the current carrying capacity of DC cables in the previous standard are overly general. Additionally, the specified overcurrent protection device fails to sufficiently address accident prevention. Furthermore, due to limited technical conditions, the standard merely provides a reference appendix for arc detection and response to malfunctions, without proposing specific design requirements.   Electrical fires are a common issue in terms of safety incidents related to photovoltaic systems, often resulting in significant property damage and loss of life. In the residential sector of the Netherlands, for instance, there were 23 fire incidents recorded in 2018, which accounted for 0.14‰ of the total number of rooftop PV system installations. The leading cause of these fires is typically attributed to arc faults. Now, let’s explore the arc faults.

Defining Arc Faults and Various Types of Arc Faults

Definition of Arc-Fault

An arc fault is a phenomenon that arises from the breakdown of the dielectric of a surrounding gas, resulting in the flow of electric current through a non-conductive medium like air. This electrical discharge generates high temperatures, often resulting in the formation of a spark or an open flame.


Wikipedia definition of Arc-Fault

Wikipedia definition: “An arc fault is a high power discharge of electricity between two or more conductors. This discharge generates heat, which can break down the wire’s insulation and trigger an electrical fire. Arc faults can range in current from a few amps up to thousands of amps, and are highly variable in strength and duration.”


Arc hazards

An arc fault not only damages or destroys surrounding insulation materials, rendering them ineffective, but it also poses a significant risk of igniting nearby materials. Various factors can contribute to arc faults in a photovoltaic system, such as loose connections, inadequate breaker maintenance, broken cables, aging or damaged insulation materials, or the presence of damp and corrosive wires. Due to the numerous wires on the DC side of the PV system, arc faults are more likely to occur.


The figure illustrates the different types of arc faults that can occur within photovoltaic systems. Essentially, an arc can be seen as a series connection between a variable resistor and a voltage source, with the arc voltage increasing proportionally to the current.


In most cases, the accumulated arc energy prior to protection activation serves as the primary parameter, which is used to establish benchmarks for assessing the effectiveness of AFCI (Arc Fault Circuit Interrupter) technology. We will delve into further explanation of AFCI technology later in this article.


Types of electric arc faults

There are three types of DC arcs:


  • Series arcs


  • Parallel arcs


  • Ground arcs


The occurrence of series arcs is the most frequent (approximately 80%) due to the specific characteristics of electrical installations and PV power generation. Parallel arcs and ground arcs are less likely to happen, but they pose greater risks when they do occur.


Arc Fault Circuit Interrupter (AFCI) Technology

The Arc Fault Circuit Interrupter (AFCI) is an advanced technology used for protecting electric circuits. This specialised interrupter is designed to not only disconnect the circuit when there is a rise in current, like a conventional breaker, but also to specifically detect and respond to the formation of an electric arc on the load. The AFCI is capable of distinguishing between harmless electric arcs, such as the spark that occurs when plugging in a device or operating a light switch, and potentially dangerous arcs that could potentially lead to a fire, such as wire scratching or cracking. When a harmful arc is detected, the AFCI promptly interrupts the circuit, effectively preventing any further fire hazards.

Working Mechanism of the Interrupter

The interrupter incorporates electronic components that monitor the frequency of the current flowing through it. When an electric arc occurs, a high-frequency signal is generated, typically exceeding 100 kHz above the standard current frequency. The interrupter’s objective is to detect and capture this signal, subsequently disconnecting the circuit. Traditional circuit breakers, however, only disconnect the circuit if the current value surpasses a certain threshold. This poses a problem because in cases where a low-level continuous electric arc is present, a fire can potentially occur without the circuit being disconnected.

In order to address the issue of electric arcs, various solutions have been introduced to the commercial market, including several options available in Arab markets. One notable solution is the Huawei AFCI (Arc Fault Circuit Interrupter) solution, which will be further explored in the next paragraph.

Technical Features of the Huawei AFCI Solution

Leading solar energy companies worldwide recognize the promising potential of distributed photovoltaic energy. However, the primary concern that needs to be addressed for distributed PV systems is the risk of electrical fires, primarily caused by arcing in the DC circuit.

To enhance the safety and control of PV plants, it becomes crucial to implement comprehensive measures, particularly intelligent arc detection and rapid shutdown technologies. Recognizing this need, Huawei has introduced inverters equipped with DC arc detection (AFCI) functionality specifically designed for distributed photovoltaic systems, including residential installations. These advanced features aim to mitigate the risk of electrical fires and elevate the overall safety and performance of PV system

Drawing upon its technological expertise and vast experience, Huawei has put forward an intelligent arc detection solution to overcome previous challenges with the help of AI BOOST AFCI technology. This innovative solution leverages the features of Arc-Fault Circuit Interrupter (AFCI) technology and integrates deep learning techniques, benefiting from Huawei’s extensive technical knowledge in the fields of information and communication technology as well as artificial intelligence.

The AI component of the solution employs a model that iterates over vast amounts of big data, enabling it to effectively differentiate signals with similar patterns, continuously detect unfamiliar spectra, and enhance its adaptability to noise. By combining these elements, Huawei’s intelligent arc detection solution offers enhanced capabilities for accurate and efficient arc detection.

Furthermore, the “AI BOOST AFCI” model has undergone significant enhancements to enable effective identification of arc characteristics across various scenarios.

Detecting arcs in DC circuits presents a challenge due to the typically weak arc noise, which is often only 0.1% of the normal current signal, making it difficult to detect. However, Huawei has successfully developed an intelligent, precise, and rapid solution by leveraging a neural network algorithm. This algorithm enables accurate detection of electric arc faults, allowing for swift protection by shutting off the inverter within 0.5 seconds. With this advanced approach, Huawei ensures efficient arc detection and timely mitigation of potential hazards.

Comparison between Traditional AFCI Solutions and Huawei’s Smart Solution

Not all AFCI solutions offer equal levels of protection, as not all inverters utilize AI technology. AFCI arc interrupters lacking AI technology and big data capabilities are prone to detection failures, thus constraining the potential expansion of PV systems. Recognizing this limitation, Huawei has enhanced its inverters with AFCI functionality that meets the stringent requirements of UL 1699B. In fact, Huawei has obtained the industry’s first high-level AFCI certification, ensuring enhanced safety and reliability in their AFCI-equipped inverters.


While companies have made significant strides in developing effective solutions for AC faults, there are still ample opportunities for further innovation and creativity in addressing DC issues, specifically electric arc faults. International companies are actively competing to offer solutions and products that ensure optimal efficiency, quality, and safety of photovoltaic systems. This race towards advancement signifies the industry’s commitment to continuously improve and enhance the overall performance and security of photovoltaic installations.




  1. July 10, 2023 at 9:34 am
    Eslam Hamdan

    Great Idea

    • July 10, 2023 at 9:36 am

      I Agree

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