Page 21 - Issue 2 2023

TECHNICAL

Understanding the basics of earth

ground testing

Information from Fluke

oor grounding not only increases of multiple ground rods; connected mesh or grid networks; ground plates; and ground
the risk of equipment failure; it is loops. These systems are typically installed at power-generating substations, central
Pdangerous. Facilities need to have offices and cell tower sites.
adequately grounded electrical systems
so that in the event of a lightning strike, Locations of resistances
or utility overvoltage, current will find a a) The ground electrode and its connection
safe path to earth. The resistance of the ground electrode and its connection is generally very low.
Simple grounding systems consist Ground rods are generally made of highly conductive/low-resistance material such
of a single ground electrode driven into as steel or copper.
the ground. The use of a single ground b) The contact resistance of the surrounding earth to the electrode
electrode is the most common form of The National Institute of Standards (a governmental agency within the US Dept.
grounding and can be found outside of Commerce) has shown this resistance to be almost negligible provided that the
homes or places of business. ground electrode is free of paint, grease, etc. and that the ground electrode is in
Complex grounding systems consist firm contact with the earth.

Figure 1: Fluke earth ground testing meters

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