Friday, April 19, 2019

By Andrew Hamilton


Individuals often feel relaxed and safe when living in buildings with effective earthing systems. Such systems are vital in ensuring that the occupants and electronics are protected from electrical surges. This is achieved by providing a safe path for the huge currents emanating from lightning and over-voltage. Thus, the lightning earthing systems require regular ground testing. This aims at ensuring that the earth resistance is low and checks the functionality of the systems.

Anciently, the technicians espoused more on the use of vintage test instruments and probes. They were principally used to induce a current in the ground between the test apparatus, that is, the test electrode and remote probe. This was followed by measuring the voltage drop on the current flowing through the embedded soil. The technicians would then use ohm principles to calculate the earth resistance around a lightning earthing system.

With advancement in testing instrumentation, the ancient test procedure was unified thus leading to the two commonly used methods. They were introduced by innovative modifications that were aimed at addressing definite needs. The alterations were also aimed at enhancing the overall operation-ability and productivity of earthing systems. Nevertheless, both approaches employ the same instruments which have been steadily modified to improve safety, accuracy, convenience, and ease of use.

One of the approaches is the fall-of-potential test method. It is carried out by complete isolation of the lightning earthing system from the power supply. It also demands the end-user to remove all the conductors that extend past the extremes of the earthing system being tested. The method is highly embraced when testing larger grounding systems. It also performs well in small field electrodes. However, it is associated with lots of drawbacks due to its lengthy procedures.

Additionally, the other approach is the induced frequency test. It is effective in that it can be performed when the power is still on. It requires the power utility to be connected to the earthing system under test. The test is accurate for small electrodes since it reads the frequencies in the kilohertz range. The range used assume elongated conductors as inductive chokes and thus do not reflect readings for the entire grounding system.

In order to generate viable data schedule for a ground test, the technicians should make use of the right procedure and effective apparatus should be employed. This increases the accuracy of findings as well as making the test to be subtler and swift. Other factors should be maintained accordingly to enhance the results. Some factors such as heavy rainfall reduce the resistance of soils than it would be under normal situations.

Moreover, with technological advancement, a refined procedure has been invented to produce more convincing and accurate results. They are computerized and thus, do not necessarily need further analysis and calculations. In addition, they do not also need one to de-energize or isolate any conductor from the grounding system being tested.

Thus, the testing procedures have undergone a series of evolution phases with an unobstructed focus of enhancing accuracy and convenience. This has also been as a result of advancement in instruments used to carry out the tests. It is a pivotal activity that aids in improving the overall functionality and safety of earthing systems.




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