An industrial portal is still responding, but the cameras have disappeared from the network. In the neighboring building, production continues even though the monitoring system is no longer receiving information from the PLCs. After a storm, this scenario can lead to looking for the fault in the wrong place: in the software rather than in the physical connections.
In Europe, North Africa, and South America, sites with multiple buildings often share a common vulnerability: their data exchanges traverse external spaces. However, protecting the power supply to a single building is not enough to address all the pathways by which a disturbance can reach its equipment.
Therefore, the right question is not simply "which surge protector should I install?", but rather "what connections link my buildings, and how are they integrated into the lightning protection system?". This article explains the mechanisms useful for understanding the risk, the limitations of copper and fiber optics, and the information to gather before conducting a study.
The goal is to build a coherent architecture, without turning a general recommendation into a universal prescription.
Can lightning damage a network without striking the building?
Yes: lightning-related disturbances can affect equipment through their power supplies or conductor connections, even when the building is not directly struck. Furthermore, the electromagnetic field associated with the discharge can induce voltages in circuits. Therefore, protection must consider all site interfaces, not just the roof.
Three mechanisms to distinguish
A transient overvoltage is a brief surge in voltage that can exceed the capacity of a piece of equipment. Electromagnetic induction is the mechanism by which a changing magnetic field produces a voltage in a circuit; it explains why the path of the cables also matters.
Furthermore, a ground potential rise is an increase in local electrical potential due to a current flowing through the ground and grounding points. Two distant pieces of equipment, connected by a conductor cable, can then experience potential differences that stress their interfaces.
- A disturbance can propagate along a conductor entering the building.
- A voltage can be induced in a loop formed by the circuits.
- A potential difference can appear between interconnected equipment.
The U.S. National Weather Service reminds us that lightning-related power surges can damage electronic equipment at a distance from the strike (NWS, indoor safety). However, this observation does not allow for the establishment of a universal safe distance around a building.
Map the connections before choosing a protection
An Ethernet cable is a connection used to carry data over a local area network; some installations also use its conductors to power equipment. Therefore, a camera connection can serve both a communication and a power function, which must be identified during the diagnostic phase.
Consider peripheral equipment
In practical terms, the initial mapping should start with the uses: access control, video surveillance, automation, telecommunications, and monitoring. A small external box may be essential for operation, even if its purchase price seems low.
For each connection, note at least:
- the buildings and equipment it connects;
- its physical support, its path and its external parts;
- the type of signal carried (Ethernet with or without PoE power, RS485 bus, telephony, coaxial link);
- the power supplies associated with the equipment located at the ends;
- the shielding, metallic elements and protections already present;
- The service will be interrupted if the connection becomes unavailable.
Next, distinguish the theoretical plan from the actually implemented process. An extension added after the site's delivery may bypass the initially planned interfaces; it therefore warrants specific documentation verification.
For example, a connection installed temporarily for a construction project can become permanent without being included in the documentation. This example is illustrative, and not a case study attributed to an LPS client: it demonstrates why the inventory must also cover minor modifications.
Copper or fiber: what the medium actually changes
Optical fiber is a transmission medium that carries information in the form of light. A fully dielectric optical link does not provide an electrically conductor path for the signal between its ends; however, this does not automatically make the entire installation lightning-proof.
Do not confuse signal isolation with complete protection
Indeed, the converters, switches, and cameras remain electrically powered. Furthermore, some optical cables contain metallic elements: their presence should be verified in the technical specifications rather than assumed to be absent.
The comparison must therefore be based on several criteria:
- The existence or not of a conductor path associated with the support.
- The power requirements of devices at the extremities.
- The constraints of flow rate, distance and environment of the project.
- The integration of metallic elements into electrical design.
- The procedures for replacing and troubleshooting the connection.
Surge protector for communication lines
For a copper connection, the appropriate device is a surge protector for communication lines, installed at the entry point of each connection in a building. It must be chosen according to the type of signal carried: Ethernet with or without PoE power, RS485, telephony, or coaxial cable.
However, copying a chosen reference for another interface can disrupt network operation or leave a protection need unaddressed. Therefore, the choice must be made link by link, taking into account the transmission and power supply characteristics of each.
Furthermore, the screens, shields, and metallic parts of the cables, including the armor of some fiber optic cables, are connected to the Equipotential Spark Gap at the building's entry point. According to the study, the grounding connections of the connected buildings also benefit from being interconnected.
Therefore, the choice between copper and fiber is not a matter of opposing "dangerous" and "invulnerable." It is an architectural decision, to be made in consultation with network and electrical specialists to address the remaining infrastructure.
IEC 62305: Treat interfaces, not just devices
The International Electrotechnical Commission, designated by the acronym IEC, publishes the IEC 62305 series dedicated to protection against lightning. Part 4 deals with electrical and electronic systems in structures and measures intended to reduce the risk of permanent failures due to the electromagnetic effects of lightning.
The third edition, IEC 62305-4:2024, was published on September 12, 2024 (IEC, official record). However, citing this edition does not exempt one from identifying the documents applicable to the country, the contract, and the installation under study.
The initial risk analysis, based on IEC 62305-2:2024, serves as the starting point for selecting measures. It is this analysis that links the chosen safeguards to the potential consequences of a service interruption.
A coordinated design
Equipotential Spark Gap is an approach that connects conductor parts according to a defined design in order to limit their potential differences. It does not consist of arbitrarily adding a connection to a piece of equipment: its integration requires a study of the entire system involved.
To prepare for this study, organize the questions in this order:
- Which services must remain available, and what would be the consequences of their loss?
- Which lines enter buildings or connect distinct areas?
- Where are the protective interfaces and Equipotential Spark Gap connections?
- How are cable trays and circuit loops controlled?
- What evidence will be used to verify the choices and their implementation?
Therefore, a lightning rod does not replace the protection of electronic interfaces. Conversely, a surge protector installed on a network connection does not, by itself, constitute a complete lightning protection system for the building.
Build a useful file for the operations teams
Resilience is the ability of an organization to maintain or restore its essential functions after a disruption. For an industrial network, it therefore combines technical protection, knowledge of the architecture, and diagnostic procedures.
Separate protection, observation and evidence
Following an event, a temporal coincidence between a storm and a power outage does not automatically prove the exact electrical cause. Nevertheless, time-stamped information facilitates analysis when compared with equipment logs and observations made by authorized personnel.
A usable file includes, in particular:
- the connection plan and the version corresponding to the terrain;
- the references of the equipment and their surge protectors;
- the available design and acceptance reports;
- the incidents observed and the actions actually taken;
- the responsibilities for diagnosis and return to service.
Before returning to service, check the condition of the surge protectors after each significant storm. Indeed, a surge protector without a fault indicator is not necessarily intact.
In this context, LPS Manager, the application for monitoring connected products LPS France, centralizes the status of Paraton@irimpact counters Compt@ir and Alert@ir XT devices. It groups together reported faults, recorded impacts and warranty tracking, with a time-stamped history for each installation.
Furthermore, Strike Radar allows for retrospective verification of lightning strikes recorded around a site on a given date, and then provides keraunic reports and lightning strike certificates. These documents are based on detection data that LPS France does not itself use; they do not replace an electrical investigation of the fault.
Finally, each device retains its function: the system Contact@ir allows for remote testing and monitoring of Paraton@irgateway Rout@ir or via cellular network with the Contact@ir MD. However, it does not protect the network ports of buildings.
Contact LPS France with your site plan to define the requirements before selecting a solution.
In summary, connections between buildings fall within the lightning protection perimeter, even when they only carry data. The chosen medium, power supplies, surge protectors, and Equipotential Spark Gap must be studied together, based on the risk analysis. Thus, accurate mapping prepares the ground for a coherent design according to IEC 62305-4:2024. The monitoring documentation then allows for explanation of the choices and a methodical approach, without promising the complete absence of faults.
