Protection against the effects of lightning

Damage caused by lightning is a problem that has been with us for many years. A system for structural and electronic protection has evolved using tried and tested methods. The Faraday cage method of protection together with a fully integrated earthing system has reached a stage where a correctly designed and installed system will give a high level of protection and reduce the effects of lightning to acceptable levels. With the sophistication of modern electronic systems the role of the earthing system is becoming increasingly important. As new types of equipment and devices use the earth as a reference and current sink, electrical noise and stray earth currents can give rise to unexpected problems. By utilising practical experience, the measured parameters now available and the high specification earthing materials currently in use it is possible to design and implement a highly effective earthing system that will overcome most problems. The paper discusses lightning protection systems (roof network and down conductors), earthing system (soil resistivity, soil enhancement compounds, equipotential bonding, touch and step potential) and electronic protection including BS6651:1992 Appendix C