Earthing plate measurements

The earthing electrode shall safeguard safety in the electrical facility. It is dependent on good connection with the surrounding ground and the degree of moisture there. Therefore it is important that the planning and designing of the electrode is adapted to both function and placement.

A well-functioning earthing electrode safeguards operational reliability in electrical installations and signal systems. Faults in the earthing electrode can lead to dangerous contact voltages. There may also be a risk that significant electronic equipment will not function or is not adequately protected against surge voltage.

Measuring using the full-scale method

There are different methods to measure transition resistance for earthing electrodes. Trainor uses a full-scale method that provides valuable additional information about the measurement set-up; among other things on whether an adequate distance from the electrode has been used, whether or not the ground is homogeneous, calculating of distance to reference point, impact from other earthing systems etc. The documentation contains all relevant parameters that are significant for future control measurements. 

A lack of knowledge about safe measuring methods has led to the use of unsafe methods for measurement of transition resistivity. An example of this is the so-called 62% rule. This method makes use of only one measurement point, which easily can lead to inaccuracy due to inhomogeneous ground and direct or indirect return coupling. Thus large errors in measurements can occur. Similar errors occur if system earthing clamps are used on complex industrial electrodes, transformer kiosks in the distribution network or high voltage masts with more than one earthing electrode. System earthing clamps and high frequency tests for earthing resistance measuring can show untrue values because it is uncertain what is being measured (continuity or transition resistance).

Correct equipment and experience

Measuring earthing resistance requires special expertise and advanced measuring equipment. As a customer at Trainor, you will receive full follow up from qualified staff with expertise in measuring methods and equipment.  Our engineers observe and provide any information about other conditions with respect to the grid that may be of significance to the company. We also offer your personnel the opportunity to participate in the measuring task to learn some of the basic principles in measuring techniques. Trainor has also developed a new system for administration of electronic measurement certificates for measuring earthing plates. Read more about our database for earthing plate measurements here.