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IAEI Magazine | Author: Todd Lottmann
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Todd Lottmann

Todd Lottmann is an electrical engineer employed by Cooper Bussmann, Inc. focusing on codes and standards. Todd is an alternate member of NEC Code-Making Panel 12 representing NEMA, a member of the UL 508A standards technical panel, member of NEMA 1IS Industrial Controls section, and involved with the NFPA 79 technical committee. Todd is the Bussmann IAEI representative participating in the national section meetings and various chapter meetings around the country.


Selective Coordination of Elevator Circuits

During the past revision cycle for the 2005 NEC, a new definition was created in Article 100 for selective coordination. The need for this definition can be taken from its creation and shows the expansion of selective coordination requirements throughout the NEC. One of the basic requirements for the creation of a definition in Article 100 is the use of the term in two or more sections of the Code. The 2005 NEC now has multiple sections containing requirements for selective coordination of overcurrent protective devices and most are contained in sections pertaining to protection requirements for critical circuits involving life safety. Compliance with these selective coordination requirements is achieved through the selection of overcurrent protective devices with appropriate operating characteristics. The choice of overcurrent protective devices with the proper operating characteristics is not difficult. However, if proper review is not given to the overcurrent protective device used, it is easy to have systems that are not compliant and, thus, systems that do not provide the proper safety of human life demanded in critical circuits.

New Short-Circuit Current Rating Requirements Facilitate Compliance with 110.10

Well, another three years has passed and with it another revision cycle of the NEC has been completed. As so often happens during code cycles, several significant changes occurred during the 2005 NEC code cycle. One of the more significant changes is the new requirement for industrial machinery electrical panels, industrial control panels, certain HVAC equipment, meter disconnects, and certain motor controllers to be marked with a short-circuit current rating. This article will discuss these new marking requirements and equipment affected, provide background information on the need for these changes, and discuss the role that the inspector plays in enforcement of these new requirements.

Arc-Flash Hazards

Electrical hazards, such as arc flash, can be extremely damaging to equipment and, more importantly, to people. An alarming number of electrically related accidents occur each year, often resulting in serious third degree burns or death. Luckily there have been recent significant advances in the electrical industry surrounding electrical hazards, particularly arc flash. The following discussion will detail the dangers and nuances surrounding arc-flash hazards and overview recent advancements in the electrical industry to minimize their occurrences.