It’s a common assumption: no rain, no storm, no problem.
But when it comes to lightning, that couldn’t be further from the truth.
The reality: lightning doesn’t need rain to be dangerous.
Lightning can strike up to 10 miles away from the centre of a storm. These are often referred to as ‘bolts from the blue’ – strikes that travel well beyond the visible storm cloud before reaching the ground.
That means lightning can occur:
- before rain begins
- after it has passed, and
- when skies appear clear locally
For building managers, site operators and anyone working outdoors, this creates a false sense of security. Just because the weather looks calm overhead does not mean the risk has gone.
Risk isn't always where the storm is
Lightning risk isn’t confined to what you can see above you. Electrical energy from a strike can travel significant distances through connected infrastructure.
For example:
- Power or other electrical lines can carry surge currents miles from the point of impact
- Metalwork, cable systems and pipework can introduce lightning energy into buildings
- Nearby strikes can create dangerous ground currents and side flashes
This is something we see in practice when working on critical infrastructure. On National Grid substations, for instance, engineers must log into a real-time lightning risk system. When risk reaches a defined level, work stops immediately, even if the storm is not directly overhead.
Why? Because lightning striking miles away can still be conducted into the site through the network.
The real cause of most lightning damage
When people picture lightning damage, they often imagine a direct strike hitting a building. In reality, most damage we see is caused by secondary effects.
The biggest culprit is electrical surges.
A lightning strike, even at a distance, can generate massive voltage spikes that travel through power and data systems. These surges can result in:
- damaged electronics
- failed building management systems
- compromised fire and security systems, and
- costly downtime and disruption
This is why surge protection devices (SPDs) are such a critical part of modern lightning protection design. Without them, even a distant strike can have significant consequences.
Lightning risk extends to people, not just structures
Lightning protection is not only about safeguarding buildings. It also plays a crucial role in protecting people around them.
Higher-risk environments include:
- Construction sites
- Industrial yards
- Schools and sports facilities
- Rooftop work or leisure areas
Even when a building isn’t directly struck, nearby lightning can create dangerous step and touch potentials. In simple terms, electric current can spread through the ground or conductive materials, putting anyone nearby at risk.
A changing risk
While no one can predict exactly how climate change will affect future weather patterns, one thing is clear: conditions are becoming more extreme and less predictable.
Warmer air holds more moisture, which can lead to more energetic thunderstorms. Combined with increasing variability in weather systems, this creates greater uncertainty for building design and operation.
As a result, forward-thinking developers and asset owners are taking a more cautious approach, incorporating lightning and surge protection as standard, rather than as an afterthought.
What the standards now expect
The importance of lightning protection is reflected in the BS EN IEC 62305 (2025) standard, which sets out how systems should be designed, installed and maintained.
Key elements include:
- Lightning risk assessment to determine the level of protection required
- Lightning protection systems including air termination, down conductors, earthing and equipotential bonding
- Surge protection devices to manage transient overvoltages
- Thunderstorm warning systems, which use detection networks to provide early alerts before lightning reaches an area
These systems are already widely used on critical infrastructure and are becoming increasingly relevant for commercial and industrial buildings.
Not a 'set and forget' solution
A common misconception is that once a lightning protection system is installed, it requires no further attention.
In reality, ongoing maintenance is essential.
Systems should be:
- inspected annually
- checked after any building modifications, and
- tested following a known or suspected lightning strike
Over time, components can degrade. Connections loosen, corrosion develops and earthing conditions change. Without proper inspection and testing, systems may not perform as intended when they are needed most.
For building managers, this isn’t just best practice, it forms part of their duty of care and can have implications for insurance and compliance.
The business impact of getting it wrong
Lightning damage isn’t just a technical issue; it’s a business risk.
Potential consequences include:
- operational downtime
- loss of critical systems or data
- fire and safety hazards, and
- costly repairs and reputational damage
With modern buildings relying heavily on sensitive electronic systems, the impact of even a single surge event can be significant.
As Matthew Waldram, Omega Red Group’s Technical and Compliance Manager, puts it in a recent episode of the Grounded in Safety podcast, ‘Clients don’t always appreciate the risks of lightning, the damage it can do and the preventative measures they could take’.
The takeaway
If you can hear thunder, lightning is already close enough to pose a risk. And even when you can’t, the danger may still be there.
Clear skies don’t guarantee safety. Lightning currents can travel and cause damage far beyond the visible storm.
That’s why effective protection starts with understanding the real risks, not the myths.
How Omega Red Group can help
From initial risk assessments through to design, installation, testing and ongoing maintenance, Omega Red Group supports organisations in managing lightning risk effectively and compliantly.
If you’re unsure whether your building or site is adequately protected, now is the time to review it. Because when it comes to lightning, what you can’t see can still cause serious harm.
To speak to our team about your lightning protection requirements, call us on: 0800 111 4040.
If you enjoyed this article, why not plug into our podcast ‘Grounded in Safety’?
Our latest episode ‘The safety foundation’ explores power earthing and what it means to have a compliant and comprehensive electrical safety system. We unpack why earthing matters, reveal the hidden hazards that often go unnoticed and break down the key components that make an earthing system truly effective.
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Read other articles in our 'Myth busters' series
