Lightning Protection 2017-04-13T13:00:01+00:00




Lightning protection testing is carried out every 11 months, so that over a 12 year period your system has been tested in every month. Here at Key Electrical we test to the BS EN 62305 standard to ensure your lightning protection system is up to date and inspected correctly.

Here at Key Electrical we have a wealth of expertise in the field, and our engineers can help you to keep your lightning protection system in good working order, to ensure it is safe for the public and your employees.

Following your test, a full report will be given detailing all inspections and tests carried out, their results, and any remedial works which may be required; if requested we can provide a quotation for their repair.


Testing of your Lightning Protection System is a requirement under the Electricity at Work Regulations 1989; testing is required to ensure that your system is fit for purpose and working correctly. The testing is carried out to the procedure outlined in BS EN 62305:2006, which is the British Standard for Lightning Protection Systems.

The Lightning Protection System should be inspected at a maximum interval of 12 months, however it is recommended that testing is carried out at 11 month intervals; this means that over a 12 year period, your Lightning Protection system is tested in every month, allowing for seasonal changes in soil resistivity.

If any faults are discovered whilst carrying out the inspection and testing, the faults will be photographed and documented, and if you require it, we will provide a quotation for their rectification.

Testing of the Lightning Protection System should comprise:

  • Performing random continuity tests, especially continuity of those parts of the Lightning Protection System which were not visible for inspection during the initial installation and are not subsequently available for visual inspection.
  • Conducting earth resistance tests of the earth termination system. The following isolated and combined earth measurements and checks should be made and the results recorded in a Lightning Protection System report:
    • The resistance to earth of each local earth electrode and, where practical, the resistance to earth of the complete earth termination system. Each local earth electrode should be measured in isolation with the test point between the down conductor and earth electrode in the disconnection position. If the resistance to earth of the earth termination system as a whole exceeds 10ohms, additional electrodes should be installed, where practicable, to obtain the requisite resistance value. If there is a significant increase in the value of the earth resistance from previously measured values, additional investigations should be made to determine the reason for the increase and measures taken to improve the situation.
    • The results of a visual check of all conductors, bonds and joints or their measured electrical continuity.


The objective of lightning protection inspection is to confirm that:

  • The Lightning Protection System conforms to the design based on BS EN 62305
  • All components of the Lightning Protection System are in good condition and capable of performing their designed functions, and there is no corrosion
    Any recently added services or structures are incorporated into the Lightning Protection System

Inspections should be carried out:

  • During the construction of the structure, especially in order to check the embedded electrodes and associated clamps and bonds
  • After installation of the Lightning Protection System
  • Periodically at such intervals as determined with regard to the nature of the structure to be protected
  • After alterations or repairs, or when it is known that the structure has been struck by lightning

It is particularly important to check the following during the periodic inspection:

  • Deterioration and corrosion of air termination elements, conductors and connections
  • Corrosion of earth electrodes
  • Earthing resistance value for the earth termination system
  • Condition of connections, equipotential bonding and fixings

Visual inspections should be made to ascertain that:

  • The design confirms to BS EN 62305 by checking the original technical design documentation where available.
  • The Lightning Protection system is in good condition.
  • There are no visible loose connections or accidental breaks in the Lightning Protection System conductors and joints.
  • No accessible part of the system has been weakened by corrosion, especially at ground level.
  • All visible earth connections are intact.
  • All visible conductors and system components are fastened to the mounting surfaces, and components which provide mechanical protection are intact and in the right place.
  • There have not been any additions or alterations to the protected structure which would require additional protection.
  • There has been no indication of damage to the Lightning Protection System, or by reference to any indicators to Surge Protective Devices.
  • Correct equipotential bonding has been established for any new services or additions which have been made to the interior of the structure since the last inspection, and that continuity tests have been performed for these new additions where practically possible.
  • Bonding conductors and connections inside the structure are present and intact where practically possible.
  • Separation distances are maintained, subject to availability of original design information.
  • Bonding conductors, joints, shielding devices, cable routing and Surge Protective Devices have been checked and tested where practicable and subject to availability of original design information.



Regular inspections are among the fundamental conditions for reliable maintenance and so effective performance of a Lightning Protection System. The property owner shall be advised of all identified faults and they shall be repaired without delay.

On completion of any repairs to the Lightning Protection System, the client should be advised and the on-site file updated so that remedial action can be considered by the Lightning Protection System engineer during the next inspection and test. If any repairs involve the earthing system, the individual electrodes repaired or enhanced should be retested and their resistances advised to the client for logging in the on-site file.