Earthing & EMC

       

Earthing of electrical systems is very important.  Its primary purpose is to ensure safety by providing protection for buildings and occupants against direct damage and electrical shock due to lightning or short circuit events.  Its secondary purpose is to provide a noise free equipotential environment to enable electrical and electronic equipment to function correctly and reliably.

Earthing of installations and equipment is an issue that crosses the boundaries of the various disciplines involved in the construction and equipping of a modern commercial or industrial building. Construction engineers need to talk with instrumentation engineers and IT professionals need to discuss matters with electrical engineers and so on.  Sometimes, however, these individual engineers do not speak the same technical language or are not even aware of the needs of each other’s installations. In A Systems Approach to Earthing an overall earthing approach is presented to serve as a basic guideline for earthing and interference suppression that can be used by multi-disciplinary teams.

The aim of Fundamentals of Electromagnetic Compatibility (EMC) is to give an overview and a basic understanding of the major physical principles of electromagnetic interference and an introduction to the principles of mitigation of disturbing effects. As a result, the measures required to achieve an EMC-compliant installation should be easily understood.

The design of earthing electrodes is covered in two application notes.  Earthing Systems - Fundamentals of Calculation and Design discusses theoretical aspects, including basic design concepts, the resistance of the earth, voltage distribution and the effect of impulse currents.  More practical issues, including the calculation of earthing resistance for various electrode shapes and configurations are discussed in Earthing Systems - Basic Constructional Aspects.