The gold standard for grounding testing is IEEE Std. 81–2025, Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System. Its purpose is to assist engineers and technicians in obtaining accurate, reliable grounding system measurements and interpreting data for design validation. This standard covers: In addition to being familiar with this standard, successful testers must …
The fall of potential (FoP) test to measure the ground impedance of a data center building or substation is commonly specified as part of start-up and commissioning testing. This test procedure is spelled out in IEEE Std. 81, IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Ground System. To obtain good data,a properly executed …
Substation design typically calls for two to six inches of aggregate (crushed rock) as a top layer upon completion of construction. This layer serves several purposes, including improved vehicle access, reduced erosion, and suppression of vegetation. Another significant function of this layer is to provide personnel safety by increasing the allowed (maximum permissible) touch and step potential values versus native …
As testers, where should we start? The standards! For grounding testing, the industry reference is IEEE Std. 81, Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System. As with most standards, familiarity and interpretation are key. It can be a challenge to understand the intent, methods, and implementation of the prescribed testing. Fall of Potential …
Soil — most think, “Hey, it’s just dirt,” but when it comes to electricity, soil becomes more complex. Electrical resistivity (resistance to current flow) is one characteristic of soil that requires specific knowledge regarding testing and application in grounding system design. Soil is made up of combinations of clay, sand, loam, and various types of rocks. These components have differing …
Everyone has heard stale jokes about not reading instructions until it becomes a last resort. With many electrical test instruments, experience or general familiarity can at least get you started. But with ground testing, taking the new instrument out of the box and trying to figure out how to run the test will get you nowhere. There is nothing intuitive …
Out of sight, out of mind is a common aphorism, but when it’s applied to standby backup batteries, it can — and does — become catastrophic. Standby battery banks support production lines, hospitals, computer rooms, and entire facilities to provide an alternate power source should utility power fail. The standby battery is the interface between a smooth transition and total …
Storms with lightning are a major cause of electrical system interruption.
Grounding and bonding are integral parts of an electrical system and must be properly understood, installed, and maintained for maximum safety and performance. Accordingly, the National Electrical Code© (NEC©) focuses on describing, defining, and regulating this element, specifically in Article 250 Grounding and Bonding of Electrical Systems. Grounding electrical systems serve the dual purpose of limiting voltages that might otherwise …
Utility substations are undergirded by large — sometimes massive — grounding grids. These are made up of electrodes, much like the familiar ground rod, but with extended responsibilities. The grid must provide a means to carry electrical currents into the earth under normal and fault conditions without exceeding operating and equipment limits. The grid must also assure the safety of …