Frequently asked questions

Lightning Protection is a network offering a low resistance path to earth in the event of a lightning strike. It comprises four parts: 

Air terminal networks
The air-terminal network is a grid section installed at roof level forming a faraday cage with cross bonding to all extraneous metalwork, roof-mounted plant and potential strike points. Where practical metallic roof coverings can be utilised as a natural conductor, eliminating the need for a roof-mounted air terminal network.

Down Conductors
Down conductors are interconnected to the air-terminal network and give the current a safe path to the earth terminations in the event of a lightning strike. Where practical structural steel and reinforcing bars can be utilised as a natural conductor, eliminating the need for externally-fitted tapes.  

Earth Termination
The earth terminations are connected to the down conductors. They are a vital part of the lightning protection system as they disperse the current into the ground safely in the event of a lightning strike. The standard that relates to such protection states an earth location when tested should not exceed 10 times the number of earths of the system and a connected system should not exceed the maximum 10 Ohms.

Surge Protection
Surge protection protects all incoming supplies and forms an integral part of the lightning protection system.

The only way to determine if a lightning protection system is required is to carry out a detailed risk assessment in line with BS EN 62305 This will determine if the structure and its occupants are at risk and if so what level of protection is required. The main considerations of BS EN 62305 are: 

• R1 – loss of human life
• R2- loss of service to the public 
• R3 – loss of cultural heritage
• R4 – loss of economic value

If you have a lightning protection system, it must be tested, inspected and certified annually. This should include, as a minimum: 

• Visual survey of the conductor system
• Visual survey of all component parts 
• Electrical resistance testing of the isolated earth locations
• Testing the conductor’s continuity and resistance to earth

The cost of a lightning protection system can vary depending on its size and complexity. Generally, a lightning protection system costs less than you might think. It’s a modest investment for a lifetime of protection.

No, they neither attract nor prevent strikes by lightning. They only intercept the strikes and provide a safe path to the ground, allowing for the safe discharge of the millions of volts in the lightning bolt.