Earth Ground Tester : Tutorial 1

                                           
                                                                Fig : 1 : Earth Ground Test

Published by : Yousuf Ibrahim Khan
Date : 9-9-2012

Earth Ground Testing :

Most facilities have grounded electrical systems, so that in the event of a lightning strike or utility overvoltage, current will find a safe path to earth. A ground electrode provides the contact between the electrical system and the earth. To ensure a reliable connection to earth, electrical codes, engineering standards, and local standards often specify a minimum impedance for the ground electrode. The International Electrical Testing Association specifies ground electrode testing every three years for a system in good condition with average up-time requirements.

Why Ground ? Why Test ?

Poor grounding not only contributes to unnecessary downtime, but a lack of good grounding is also dangerous and increases the risk of equipment failure.Without an effective grounding system, we could be exposed to the risk of electric shock, not to mention instrumentation errors, harmonic distortion issues, power factor problems and a host of possible intermittent dilemmas. If fault currents have no path to
the ground through a properly designed and maintained grounding system, they will find unintended paths that could include people. The following organizations have recommendations and/or standards for grounding to
ensure safety:

• OSHA (Occupational Safety Health  Administration)
• NFPA (National Fire Protection Association)
• ANSI/ISA (American National Standards Institute and Instrument Society of America)
•  TIA (Telecommunications Industry Association)
•  IEC (International Electrotechnical Commission)
• CENELEC (European Committee for Electrotechnical Standardization)
•  IEEE (Institute of Electrical and Electronics Engineers)

However, good grounding isn’t only for safety; it is also used to prevent damage to industrial plants and equipment. A good grounding system will improve the reliability of equipment and reduce the likelihood of damage due to lightning or fault currents. Billions are lost each year in the workplace due to electrical fires. This does not account for related litigation costs and loss of personal and corporate productivity.