As society continues to evolve and the degree of electrification increases, our reliance on electricity grows stronger, and its usage spans a wider range. However, concurrently, the occurrence of electrical fires is also on the rise. According to the Ministry of Emergency Management, in 2018 alone, there were 137,000 fire alarms nationwide, resulting in 1,407 deaths, 798 injuries, and direct property losses of 36.75 billion yuan. Electrical fires accounted for 34.6% of the total number of fires. In recent years, there have also been frequent fire accidents in ancient buildings, such as the 2013 fire in the Small Luoshui village of Lugu Lake Scenic Area in Yunnan Province, the 2017 fire in the Zhuge and Changle villages of Lanxi City, Zhejiang Province, and the 2017 fire in the ancient architectural complex in Shunqing, Sichuan Province. Investigations following these incidents revealed that all were electrical fire accidents.

Traditional Chinese architecture, predominantly constructed of brick and wood, has a low fire resistance rating and is prone to fires due to its close proximity. Many ancient structures are courtyard-style buildings, with houses adjacent to each other. If fire control is not timely, it can quickly spread to surrounding buildings, resulting in severe damage. Therefore, fire poses a significant threat to the safety of ancient architecture. On the other hand, with the rapid spread of culture and the booming tourism industry, the number of open ancient structures and cultural heritage sites is increasing, making them crucial resources for public tourism, visits, learning, and research. To provide better visitation conditions, many ancient buildings have introduced power sources and modern electrical equipment. Without effective preventive measures, this inevitably increases the risk of electrical fires, leading to irreversible consequences.

In light of this, this article analyzes the causes of electrical fires and proposes several targeted preventive measures and management strategies.

Analysis of the Causes of Electrical Fire in Ancient Buildings

Overload-induced aging of electrical equipment

In recent years, with the continuous innovation in technology and the increasing variety of electrical appliances, there has been a growing demand for electricity in ancient buildings due to the enthusiasm for innovative applications of modern equipment in such structures. This annual rise in electricity needs is exacerbated by the improper selection of switches and cables, which can lead to equipment or conductors operating in an overloaded state for extended periods. This results in electrical equipment overheating and accelerates the aging process.

During large-scale events, if electricity usage is not controlled, it often exceeds the capacity of existing electrical installations, leading to overcurrent phenomena. The use of a large number of dimming devices and LED lights commonly results in phase shift and increased neutral current. As equipment usage time increases, the current can pierce through aging insulation layers, causing short circuits, generating significant heat and sparks, and potentially triggering fire accidents.

Therefore, during the application of electrical equipment, consider the actual power supply capacity and promptly inspect and replace electrical equipment.

(2) Neglect in management and improper usage of electrical equipment

Currently, the uses of ancient architecture primarily include residential, visitation, education, and commercial purposes. In residential ancient buildings, due to the general lack of safety awareness and professional knowledge among residents, electrical equipment maintenance and management are often neglected, which can easily lead to electrical fire accidents. For entities involved in tourism, education, teaching, and business, although there are usually management departments responsible for electrical equipment maintenance and management, and strong fire prevention awareness, electrical fire accidents have also occurred in the past. The issue of electrical safety cannot be overlooked.

Additionally, improper use of electrical equipment is also a factor contributing to electrical fires, such as when circuit breakers have improperly set protection parameters, losing their electrical protection capabilities; operating circuit breakers with loads can increase the frequency of arc extinguishing, reducing equipment lifespan and increasing failure rates; using mobile power strips to connect too many electrical devices can lead to overloading of wires; and using heating electrical equipment to dry clothes, etc.

In summary, to minimize the occurrence of electrical fire accidents, the management of electrical equipment should be strengthened and the standardization of electrical equipment usage emphasized, regardless of the use of ancient buildings.

Lightning strike

Ancient architectural structures, with their unique types, usage, and geographical environments, differ from typical buildings. Temples, Taoist temples, and similar structures are often sited in elevated areas, such as mountain peaks or slopes. Even though royal palaces and parks are located in plains, their architectural forms are towering, making ancient buildings particularly susceptible to lightning strikes.

Lightning, as a normal and widespread natural phenomenon, possesses characteristics such as high voltage, large current, and extremely short discharge time, making it highly destructive. Direct lightning strikes and induced lightning can damage power lines and electrical equipment, increasing the failure rate of devices and potentially causing electrical fires. In severe lightning conditions, it can even directly threaten human life safety. To prevent accidents caused by lightning, the lightning protection of ancient buildings' electrical systems becomes particularly crucial.

Prevention and Control Measures & Management Strategies

(1) Electrical Inspection

Manual inspection of electrical equipment operation and potential electrical fault hazards is a direct and effective electrical fire prevention and control measure. The inspection work includes:

1) Utilization and Operation of Electrical Equipment

Inspect the appearance and operational conditions of the equipment. This includes the condition of the cable insulation; surface temperature of the equipment, temperature at electrical contact points, and crimping status; current, voltage, and balance of three-phase current, etc. In case of any anomalies, check the electrical equipment individually, analyze the cause of the problem, and implement solutions such as modifying the circuit, adjusting three-phase loads, or replacing equipment to resolve electrical issues and faults.

B. Inspect the installation of electrical equipment. Electrical equipment and wiring should not be directly mounted on wooden combustible structures. Fire prevention and isolation measures must be implemented, such as using metal conduits for wiring; electrical outlets, switches, and other equipment should be installed with fire-resistant and insulating treatments; and the installation locations of lighting fixtures should maintain a safe distance from flammable materials.

Inspect the operation of electrical equipment. If there is a situation of circuit overload due to串联 of mobile power outlets, solutions can be adopted such as adjusting and increasing power supply circuits; If there is difficulty in power-off operations due to the unreasonable installation position of switch and socket panels, the position of the switch and socket panels should be reasonably adjusted; Flammable materials around electrical equipment should be cleared promptly; Electrical equipment used outdoors should have corresponding waterproof capabilities.

Electrical and fire safety inspections are conducted in accordance with the relevant provisions of the "Fire Protection Law of the People's Republic of China," ensuring that the installation, use, and design of electrical products, as well as the layout and installation of electrical and pipeline systems, comply with national fire safety technical regulations. Electrical fire safety inspections are one method to verify whether electrical installations and usage meet standards and are an essential means for preventing and controlling electrical fires. Utilizing advanced technology instruments, these inspections provide a comprehensive check from a professional and scientific perspective, accurately reflecting the danger level and location of electrical fire hazards and offering remedial suggestions to eliminate risks and prevent electrical fire accidents. Historical building units should carry out electrical and fire safety inspections at least once a year. As historical buildings often serve as exhibition rooms or galleries, and may frequently adjust their displays, inspections should also be conducted when modifying electrical wiring or replacing electrical equipment. Any identified hazards must be promptly rectified until the inspection is passed.

(2) Electrical Equipment Upgrade

Electrical safety life refers to the duration for which an electrical device maintains or essentially retains its original performance. For electrical equipment within general buildings, the following four factors are primarily considered when determining safety life.

1) Economic lifespan: Refers to the reasonable service years of equipment from an economic perspective, which is the years of service of the equipment's average annual cost. The total cost includes the initial purchase cost and the annual operating costs during the use process.

2) Technical lifespan: It refers to the duration after which a piece of equipment can continuously meet the user's functional needs. The length of this period is primarily determined by the user's requirements and the speed of technological advancement. The higher the demand and the faster the technological progress, the shorter the technical lifespan of the equipment.

3) Depreciation Life: The time it takes for the net value of the equipment, after deducting the scrap value, to depreciate to near zero.

4) Physical Lifespan (Natural Lifespan): Refers to the entire duration from when a device is new and starts being used, to its aging and eventual damage until it is retired, primarily dependent on the rate of wear and the extent of aging.

Considering safety, the aging and damage of equipment are one of the direct causes of electrical failures and fires. Additionally, with the continuous development of technology, electrical equipment is also being continuously updated and replaced. Compared to older equipment, the failure rate of new equipment is decreasing, and the safety factor is improving.

In the electrical safety management of ancient structures, the safety of ancient buildings takes precedence. Therefore, both the physical and technical lifespans should be given priority. Based on this, electrical equipment should be updated in accordance with industry requirements and product specifications. Additionally, the usage environment should also be considered comprehensively. In poor environments, increased inspections should be conducted, and the service life should be appropriately shortened, with early replacements to prevent electrical accidents.

(3) Lightning Protection for Electrical Equipment

Currently, ancient buildings are generally equipped with lightning protection systems (such as lightning rods, lightning arresters, and grounding lines), significantly reducing the danger posed by direct strikes. It is important to note that even when thunderclouds are nearby but do not directly strike the building, metal equipment around the structure can still generate induced currents, which can cause severe interference and damage to electrical equipment. In severe cases, these induced lightning strikes can produce high heat, potentially leading to fires. Additionally, the high potential of direct and induced lightning can侵入 ancient buildings or power substation through the lines, causing even greater harm. To eliminate electrical fires caused by lightning, the installation of electrical lightning protection systems is crucial. Distribution boxes should be installed with SPDs (surge protectors) and these devices should be inspected and maintained annually before the thunderstorm season, checking for any damage caused by lightning to ensure the SPDs remain effective. Furthermore, indoor electrical equipment should be equipped with lightning protection outlets (surge protection outlets) to prevent induced lightning from causing harm to end-users and personnel within the building.

(4) Electrical Fire Monitoring System

Electrical fire hazards such as leakage, short circuits, poor electrical contacts, or overheating due to overloading are often difficult to detect during routine inspections. In response to such issues, electrical fire monitoring has emerged as a new method for identifying problems and reducing accidents. This system is primarily used to monitor and control the daily operation of distribution lines, and can immediately sound an alarm in the event of a fault in the electrical system or the presence of fire hazards, thereby more accurately and promptly eliminating electrical safety risks.

China's ancient architecture exhibits a pattern in its plan layout, where residential, palace, temple, and other buildings are arranged in courtyards, formed by a series of single structures surrounded by corridors and walls. This is known as the courtyard cluster layout. From the perspective of power supply management, it is advisable to adopt a radial layout in the selection of low-voltage distribution system wiring methods. This means that the power supply for each courtyard is controlled separately, with each power loop equipped with an electrical fire monitoring system. Additionally, functional interfaces compatible with the ancient architecture's plan and geography are created on the WEB and mobile platforms, ensuring accurate alarm of electrical fire hazards.

3Ankoire Electrical Fire Monitoring System

(1) Overview

The Acre1-6000 Electrical Fire Monitoring System is a fully digital, independently-operating system developed by Ankorui Electric Co., Ltd. in accordance with current national standards. It has passed the fire product testing certification by the National Fire Product Quality Supervision and Inspection Center and all systems have successfully undergone rigorous EMC electromagnetic compatibility tests. This ensures the safe and normal operation of the series in low-voltage distribution systems. The system is now in mass production and widely used across the country. By collecting and monitoring signals such as residual current, overcurrent, overvoltage, temperature, and fault arcs, the system can prevent and alarm early signs of electrical fires. It can also disconnect over-standard distribution circuits detected with residual current, temperature, and fault arcs upon necessity. Additionally, it can meet the data exchange and sharing requirements with the AcreIEMS corporate microgrid management cloud platform or fire automatic alarm systems, as per user needs.

(2) Application Scenarios

Ideal for intelligent buildings, high-rise apartments, hotels, restaurants, commercial complexes, industrial and mining enterprises, key fire protection units, as well as the oil and chemical, cultural and educational, healthcare, financial, and telecommunications sectors.

(3) System Architecture

(4) System Features

The monitoring equipment can receive residual current and temperature information from multiple detectors. When an alarm is triggered, it emits both sound and light alarm signals. Simultaneously, the red "ALARM" indicator light on the device illuminates, the display indicates the alarm location and type, records the alarm time, and the sound and light alarm persists until the "RESET" button on the device or the "RESET" key on the touch screen remotely resets the detector. The sound alarm signal can also be manually silenced using the "Mute" key on the touch screen.

When the monitored loop alarms, the control output relay closes to control the protected circuit or other equipment. Upon alarm clearance, the control output relay releases.

Communication Fault Alarm: When there is a communication failure between the monitoring equipment and any connected detector, or when the detector itself fails, the corresponding detector on the monitoring screen will display a fault alert, and the yellow "Fault" indicator light on the device will illuminate, along with an alarm sound. Power Supply Fault Alarm: In the event of a failure in the main power supply or the backup power supply, the monitoring equipment will emit an audio-visual alarm signal and display fault information. Users can access the corresponding interface to view detailed information and deactivate the alarm sound.

In the event of residual current, over-temperature alarms, communication, or power failures, the alarm location, fault information, and alarm time are stored in the database. Similarly, records are kept when alarms are lifted and faults are rectified. Historical data offers various convenient and quick search methods.

(5) Configuration Solutions

4 Closing Remarks

By analyzing the structural characteristics of ancient buildings and considering the recent increase in electrical fire incidents, the importance of electrical fire prevention and control has been clarified. The causes of electrical fires in ancient buildings have been analyzed, and corresponding prevention strategies and management measures have been proposed, providing reference suggestions for the prevention, control, and management of ancient building fires.