What is a lightning conductor?

Lightning conductor (or a lightning rod, as they call it in the US) is a metal rod which starts from the roof of the building and leads to the ground. It’s designed to protect buildings from lightning strikes. 

There are different types of lightning conductors; they can be hollow or solid; pointed or rounded. However, one thing is always true about lightning conductors – they’re all made from conductive materials, most commonly alloy, aluminium or copper.

How does a lightning conductor work?

There are many technical ways to describe how a lightning conductor works but the concept behind it is surprisingly simple. A lightning bolt is constantly looking for the path of least resistance to the ground. The lightning conductor provides just that – a straight, fast track for the electric current to use. It’s as straight-forward as this. 

There is no guarantee that the lightning won’t “jump” and choose a different path on its way to earth. However, if your building is equipped with a lightning conductor taller than the building itself, this provides the lightning with what should be the perfect route to take. 

It must be noted, however, that a single lightning conductor is usually only an element of a larger lightning protection system, which contains multiple lightning conductors.

What does a lightning conductor do?

In essence, the lightning conductor does exactly what it says on the box – it provides lightning protection.  This means that a lightning conductor is of no use until there is a lightning strike right where your building is. Upon hearing this, you might think that the chances of this happening are too low and that the lightning conductor is all but unnecessary.  

However, before you cross the lightning conductor out let’s have a look at what it does, or even what happens if you don’t have one installed. The lightning conductor has three main functions: to protect the structure of the building, the people in and around it, and the electrical equipment used. Here’s a little bit on what dangers it protects you against. 

Property fire caused by lightning

What happens to a building if it’s hit by lightning? As you know the lightning conductor provides a straight path for the lightning to reach the ground. However, if you don’t have lightning protection, your building is in serious risk of fire caused by lightning. From starting a fire via a shortcut in the electrical circuit to burning through the very materials integral to the structure of the building (such as wood, gas and electric pipes), a lightning fire can cause serious damage. The worst part is that it usually goes unnoticed at the beginning, which means it’s definitely worth investigating in a good fire alarm. 

Injury and death by lightning

The electric current carried by lightning is such high-voltage that it can be lethal, even if a person is exposed to it for milliseconds only. Sometimes, the electricity will, in a way, roll across a person’s skin without going through the body, causing only minor injuries (such as the infamous fern-like patterned burns on the skin). Of course, there also are cases where the unlucky victim of a lightning strike is lucky enough to go through the experience unscathed. That being said, on average, in the UK,  30 people are injured and two people die as a result of lightning strikes per year. 

Damage to electrical equipment by lightning 

If the electric current contained in lightning is strong enough to kill a person, it definitely can destroy any electric appliance. The sur-charge of electricity caused by a lightning strike will cause the wires to burn and can even cause power cuts. 

Does my building need a lightning conductor?

If talking about all the dangers a bolt of lightning can cause hasn’t convinced you about the need to look into installing a lightning conductor, let’s talk about it a bit further. 

If you’re wondering whether or not lightning protection for buildings is obligatory in the UK, the short answer is ‘No’. According to the lightning protections regulations (as satiated in the RC 35 ‘Protection of buildings against lightning strikes’), it is not a legal requirement. Having said that, you’re required by law to carry out a fire risk assessment every 6 to 12 months. If during a fire risk assessment your building is identified as being at high risk of being hit by lightning, then you would have to install a lightning protection system. 

Some of the main factors which are taken into consideration when deciding the threat level are the building’s size and height, as well as the number of lightning strike incidents nearby. The bigger and taller the building is, and the higher the density of lightning strikes in the region, the higher the lightning danger level will be. 

Lightning Protection System Regulations

For buildings that are required to comply with lightning protection standards, the exact standards that apply depend on the year when your property was built as follows:

• Built before 2006 -> You must prove that you comply with the old BS EN 6651 requirements and that you were compliant with them before 2006; if the latter isn’t possible, you must comply with the BS EN 62305 standards instead 
• Built after 2006 -> You must comply with the new BS EN 62305 standards 

IEC/BS EN standards

The International Electrotechnical Commission (IEC) dictates the current  IEC/BS EN 62305 standards for lightning protection. Those are applicable not only in Great Britain but also internationally. These standards outline the necessary steps you need to take to adequately protect a building and the people in it from damages caused by lightning. 

The IEC/BS EN 62305 standards are a legal requirement for buildings used as workplaces, as per The Electricity At Work Regulations 1989. To achieve regulatory compliance such buildings are subject to a risk assessment which should determine if the lightning protection in place is suitable or if it needs to be updated. 

BS EN 6651 certification 

If you have been compliant with the BS EN 6651 standard since before 2006 and you can prove it, you still need to conduct regular checks and testing to ensure that the various elements of your lighting protection system work as intended. 

If you haven’t been maintaining your lighting protection system regularly in line with BS EN 6651 or if you can’t prove your compliance prior to 2006, you will have to schedule a risk assessment of your property and take the necessary steps to comply with BS EN 62305 instead. 

IEEE standards

The Institute of Electrical and Electronic Engineers (IEEE) implements the IEEE 80 protection standard which details a complex design process (to replace the simple risk assessment) specific to substations. The standard is not widely applicable in the UK at the moment, as it is geared towards countries that regularly deal with lightning storms. 

However, if you are responsible for a site with a complex structure that involves multiple buildings, hazardous areas or low-voltage (LV) supply lines that may be affected by a lighting surge, you will probably be required to follow the IEEE standards as well. 

Speak to your fire safety expert for more information.

Liked our article about the lightning conductor? Lightning protection isn’t the only thing we write about! Check out our article about standpipes, emergency lighting or dry powder extinguishers. 

FAQ

What is a lighting protection system?

Your lightning conductor acts as a lightning protection system. Its goal is to prevent or minimise property damage caused by lightning strikes. The system usually consists of a metal rod which intercepts the lighting before it strikes the building and conducts it safely into the ground using a wire. 

However, it is important to note that due to the high voltage carried by bolts of lightning, no lighting conductor can give you a 100% protection guarantee. Lighting protection systems divide the electrical current but the side flashes that result from this division may still ignite a fire or cause injury. 

Why should I have a lightning protection system in place?

Having a lighting protection system in place helps prevent electrical fires during a lightning storm and reduces the likelihood of electrocution due to a lightning strike. 

What is a lighting surge or spike?

After the initial lightning strike, transient overvoltages can occur between two or more conductors. Those are commonly referred to as “surges” or “spikes”.

What are the potential damages from a lightning strike or surge?

Both the initial lighting strike and the potential secondary surges pose health and safety risks, as well as risk of property damages, including:

• Death 
• Serious injury
• Fire
• Structural damage to buildings 
• Plumbing system damages 
• Damages to electrical equipment & computer systems
• Loss of data
• Loss of phone line connection 

Is lightning protection required on buildings?

Although having a lighting protection system in place is not a legal requirement in the UK, it is highly recommended that you equip your building with a lighting conductor as part of your fire safety prevention plan. 

Where can I find the official guidance for lightning protection?

IEC/BS EN 62305-1 provides you with the general lighting safety standards observed in the UK. 

What can I do to best protect myself against lightning strikes?

To get the best protection against lightning, you should invest in a lighting conductor for your property. 

You should also follow some simple rules, such as:

• Unplug non-essential appliances before you exit the building
• Stay away from trees, metal objects and poles during a thunderstorm
• Avoid using landlines during a thunderstorm as phone lines can be electricity conductors 
• If you are outside during a thunderstorm, stay close to the ground and away from metal objects