Ground Fault Protection in Circuit Breakers

Jeffrey R. Jowett, Megger Columns, Fall 2023 Columns, Tech Tips

Commissioning and maintenance procedures for low-voltage circuit breakers may include testing to determine whether the circuit breaker is able to respond correctly to faults or overload conditions as specified in the coordination study. This requirement may include ground fault (GF) as part of the protection scheme. Testing may be performed through primary or secondary injection; primary injection is the best …

Advancements in Battery Ground Fault Location

Jeffrey R. Jowett, Megger Columns, Summer 2023 Columns, Tech Tips

There is always room for improvement. In electrical testing, this is particularly true because of the rapid development and application of the underlying electronics. Although a job may be proceeding with maximum satisfaction, it may well be made easier, faster, more accurate, and safer.  For example, standby battery banks can develop ground faults over time through leaking electrolytes, accumulation of …

Using Grounding to Locate Cable Faults

Jeffrey R. Jowett, Megger Columns, Spring 2023 Columns, Tech Tips

Locating faults in buried or concealed cable is one of the most demanding, inventive, and interesting chores in all of electrical maintenance. The operator’s skills, knowledge, and ingenuity are paramount. When the power goes out, an entire facility, neighborhood, or community can be abruptly shut down without warning. Normally, this goes largely unnoticed as the utility seamlessly switches to another …

Ground Enhancements: An Answer to Difficult Grounding Situations

Jeffrey R. Jowett, Megger Columns, Tech Tips, Winter 2022 Columns

As part of the electrification of a facility, it is commonly thought that merely connecting the system to a driven ground rod means that the building is grounded. It’s not that simple. By pure luck, such an approach may indeed work. But the considerable value of the building, the efficiency of operation, the wealth of information and knowledge that is …

Ungrounded Systems

Jeffrey R. Jowett, Megger Columns, Fall 2022 Columns, Tech Tips

“What’s in a name?” asked Shakespeare. The quote is so widely known because it’s so widely applicable. In the electrical industry, the terms “grounded” and “ungrounded” are commonly applied to electrical systems. They are often taken for granted or misunderstood. How can a grounding electrode be present, and yet the system is termed “ungrounded?” It is beneficial and productive to …

Safety Testing of EV Chargers

Jeffrey R. Jowett, Megger Tech Tips, Columns, Summer 2022 Columns

Electric vehicles are prominently heralded as the trend of the future, a vital part of many planned economies’ efforts to combat global warming, widespread pollution, and the squandering of resources. But there has also been negative publicity over safety issues like car fires. The key to enjoying the best of both worlds — excellent performance under complete safety — is …

Ground Faults in Photovoltaic Systems

Jeffrey R. Jowett, Megger Columns, Spring 2022 Columns, Tech Tips

Solar farms, which are exposed to the elements, are especially at risk for failure and require dedicated electrical maintenance. Good grounding is essential, as the panels produce high DC voltages that can be sources of shock and fire, as well as induced voltages and electromagnetic interference on lines. With respect to grounding, there are two types of photovoltaic (PV) systems: …

Grounding and Bonding Meter Sockets

Jeffrey R. Jowett, Megger Columns, Tech Tips, Winter 2021 Columns

In an actual reported case, a severe storm blew down a large tree that struck a residence. A meter that should have been reporting 240 V reported a phase-phase voltage of 124 V. The falling tree had pulled down the service, which had then been re-attached by a service crew. A routine voltmeter check revealed 118 V between the left hot leg and neutral, …

The Importance of Grounding Renewables

Jeffrey R. Jowett, Megger Columns, Fall 2021 Columns, Tech Tips

The rapidly developing industry of renewable power generation can be compared to an hourglass. Inexhaustible supplies of free resources — sun and wind — are converted into a corresponding outflow of electrical energy at notable return on investment. But the process includes the neck of the hourglass through which the resources must pass. This is the solar array or wind …

Earth Resistivity Test Methods and Evaluations

Jeffrey R. Jowett, Megger Columns, Summer 2021 Columns, Tech Tips

Ground testing is often thought of as ground electrode testing: the measurement of the resistance associated with a particular rod or grounding system. A useful corollary to this is soil resistivity testing. Resistivity is the electrical property of soil itself that determines how well it can carry current. It varies enormously (Table 1) depending on physical and chemical composition, moisture, …