A single lightning event can damage far more than a switchboard. On an industrial site, the resulting transient can travel through power, communications, instrumentation and control cabling, taking out PLC inputs, variable speed drives, field transmitters, networking hardware and safety systems. Industrial lightning protection systems are therefore not a standalone accessory. They are a coordinated protection strategy for plant availability, personnel safety and asset life.
For mines, water facilities, processing plants, rail infrastructure and remote energy assets, the exposure can be substantial. Long cable runs, elevated structures, outdoor equipment and electrically noisy environments all create pathways for lightning energy and induced surges to enter sensitive equipment. The practical question is not simply whether a site needs a lightning rod. It is how each likely entry path will be managed.
What industrial lightning protection systems include
An effective system has two connected functions: managing the direct-strike risk to a structure and limiting damaging overvoltages within electrical and electronic systems. Neither function fully replaces the other.
External lightning protection is designed to intercept a strike and conduct its energy safely to earth. Depending on the structure and assessed risk, this may include air terminals, catenary wires or mesh conductors, down conductors, test points and a suitably designed earth termination system. The arrangement must suit the building geometry, roof materials, hazardous areas, nearby structures and the potential consequences of a strike.
Internal protection controls the voltage difference that can appear across equipment during a lightning event or switching transient. This is primarily achieved through surge protective devices, equipotential bonding and correct cable routing. Surge protection is required at the points where services enter a building or enclosure, then coordinated downstream to protect equipment with lower impulse withstand capability.
A well-designed installation treats the external and internal systems as one engineered outcome. A direct strike may be diverted to earth, but the rapid change in earth potential can still create damaging voltage differences on incoming cables. Similarly, a surge protective device at a main switchboard cannot adequately protect a remote PLC panel at the end of a long cable run without appropriate downstream protection.
Why control systems are particularly vulnerable
Modern industrial operations rely on electronics that operate at low signal levels and communicate across extensive networks. A 24 VDC control supply, 4-20 mA loop, Ethernet connection or encoder signal may be connected to equipment metres or kilometres apart. During a lightning event, those conductors can carry induced energy even where no direct strike occurs.
The visible failure is often only part of the cost. A failed power supply or I/O module can stop a conveyor, pump station, packaging line or process area. Less obvious damage can degrade communications ports, sensors or drive control boards, causing intermittent faults that consume maintenance time long after the storm has passed.
Protection must therefore extend beyond mains power. Signal, data, RF, coaxial, telephony and low-voltage DC circuits should be assessed wherever they cross between buildings, run outdoors or connect to exposed field equipment. The selected device must match the circuit’s operating voltage, current, bandwidth and signal type. Applying a general-purpose power surge device to an instrumentation loop can compromise signal performance or provide inadequate protection.
Building a coordinated protection approach
Surge protection works best in stages. A high-energy device at the main incoming supply is intended to manage a major portion of the incoming transient. Protection at distribution boards then limits remaining energy closer to critical loads. A final device at a machine panel, rack or sensitive instrument provides a lower residual voltage at the equipment terminals.
This coordination matters. If every device is selected in isolation, the device closest to the source may be overloaded or the final protection level may not be low enough for the connected electronics. Cable length between devices, conductor sizing, earthing arrangement and upstream protective devices all influence the result.
A practical review should cover:
- the site electrical supply arrangement and main switchboard configuration
- exposed structures, rooftop equipment and outdoor field installations
- incoming mains, generator, solar, communications and instrumentation services
- critical control panels, drives, PLCs, SCADA equipment and safety systems
- earthing, bonding and separation between power and signal cabling
- the consequence of downtime for each process area.
Earthing and bonding determine system performance
Surge protective devices do not make energy disappear. They divert transient energy to the earthing and bonding system. If that path is poorly designed, excessively long or disconnected, the voltage seen by protected equipment can remain high.
Low-impedance connections are particularly important. Short, direct conductors with appropriate cross-sectional area reduce inductive voltage rise during fast transients. A neat but long earth lead coiled inside a panel can materially reduce the effectiveness of a surge device. Installation location and conductor routing are engineering considerations, not minor finishing details.
Bonding also requires care on sites with multiple buildings, distributed field assets or separate earth systems. Potential differences between structures can be imposed on metallic services and communications cables during a strike. Fibre isolation, correctly selected data protection and intentional bonding arrangements may all form part of the solution, depending on the network architecture.
Standards, site conditions and risk assessment
Australian projects should be assessed against applicable requirements, including AS/NZS 1768 for lightning protection and the relevant electrical installation, equipment and industry-specific standards. Compliance is not achieved by fitting a device marked with a standard number. The complete installation, including the structure, conductors, earth system, cable entry points and equipment interfaces, needs to suit the site.
Risk assessment should account for lightning density, structure height and location, service connections, occupancy, hazardous materials, environmental conditions and the economic impact of an outage. A remote elevated facility with radio infrastructure and long overhead services presents a different risk profile from an enclosed metropolitan plant with underground services.
There are trade-offs in every design. Higher protection levels and more extensive coverage increase upfront cost, but can be justified where replacement parts are expensive, access is difficult or a process interruption carries high production, environmental or safety consequences. Conversely, over-specifying devices without considering the earthing system and protected circuit can deliver poor value.
Specification mistakes that create avoidable failures
The most common issue is treating protection as a single main-board device. This may reduce incoming energy but leaves remote equipment and data circuits exposed. Other frequent problems include selecting the wrong voltage rating, overlooking backup protection requirements, using unsuitable devices in harsh or hazardous areas, and failing to allow for short-circuit current ratings at the installation point.
Another mistake is ignoring equipment replacement and maintenance. Surge protective devices have a finite service life because each event places stress on their internal components. Many industrial devices include visual status indication or remote signalling contacts so maintenance personnel can identify a degraded module before protection is lost. These indicators should be incorporated into inspection routines and, where appropriate, connected to the site monitoring system.
External systems also require periodic inspection. Corrosion, construction changes, damaged conductors, loose connections and altered roof equipment can affect coverage and continuity. Any major electrical upgrade, communications expansion or building modification is a sensible trigger to review the existing lightning protection design.
A practical path from assessment to installation
Start with the critical assets and their consequences of failure. Identify what must remain operational, what is difficult to replace and what equipment is connected beyond the building boundary. From there, map the power and signal paths into each critical system.
The next step is to select compatible protection at each layer: incoming supply, distribution, machine or control panel, and exposed signal or communications interfaces. Confirm the earthing and bonding arrangement before installation, then verify device status and system continuity as part of commissioning.
For projects involving automation, drives, instrumentation and control panels, technical support during specification can prevent mismatched protection devices and late-stage redesign. Tech Source can assist project teams with Novaris surge protection selection alongside the wider power, control and automation equipment requirements.
The right protection strategy is one that reflects the real operating conditions of the site, not a generic bill of materials. Assess the pathways, protect the critical interfaces and make surge protection a maintained part of the plant reliability plan.