The discovery of electricity has been a necessity and major convenience for everyday living. It has become so essential that when we are met with power outages, whether it may be at home or at work, you might come face to face with boredom or the inability to progress. The disruption of power can result from many different reasons. The few that come to mind are the weather, excavation, or even car accidents involving power lines. Repairs could take anywhere from hours to weeks depending on the severity of the damage, and you could be without power for the entire duration. While it is an option, some residents have generators to supply power to their homes in the case of such events. For most facilities however, it is a requirement by code for power systems to have critical operations. Article 708 of the National Electric Code (NEC) plays an immense role in public safety, emergency management, national security, and business continuity.
The Importance
Critical Operations Power Systems (COPS) is the title of the article. It talks mainly about “the installation, operation, monitoring, control, and maintenance of the portions of the premises wiring system intended to supply, distribute, and control electricity to designated critical operations areas (DCOA) in the event of disruption to elements of the normal system” (Earley, NEC). This article makes sure that areas or systems deemed necessary by the authority having jurisdiction will establish some sort of emergency power source with methods of management. Common DOCA includes healthcare facilities, office/government buildings, and academic facilities.
With a focus on healthcare facility design, we can argue that hospitals and other healthcare facilities rely the heaviest on a functioning power system. There are patients that depend on the operation of their equipment to stay alive, and some others might require an MRI/PET scan. These are just a few examples to list, but all these processes are successful because there is a working power system in place. Now what happens when power is cut off and there isn’t a backup plan? There is an enormous potential for loss of life and new patients can’t be admitted for treatment. If the lights weren’t battery powered, then evacuation of the building would be near impossible due to the lack of egress lighting. These are just the issues seen immediately. More dangerous problems that hospitals share with any other commercial building is the fire alarm/protection system. With the integration of critical power in a power system, medical equipment and emergency systems that need a continuous supply of electricity can run without worry.
How Does it Work?
Equipment and systems determined to be on emergency power will need to be fed from an automatic transfer switch (ATS). These switches will need to comply with article 708.24(C)(1) and (C)(2) of the NEC. An ATS will have a load side that feeds the equipment and systems, and the ATS itself will be fed from both the normal power and emergency power. If everything is running smoothly in a building, then the loads will be supplied by the building’s normal power. Should this normal power be cut off for any reason, the ATS will automatically switch its source of power to a generator. There could be a loss of power for up to 30-45 seconds during its switching transition.
Understanding and following code is extremely important for many safety and security reasons. This applies to everything and not just critical power systems or even within the NEC at all. You never know when things will go wrong, and most of the time these codes exist because those things have gone wrong before. With how unpredictable accidents may be, taking preventative measures should be adopted wherever possible.
References:
Earley, M. W., Sargent, J. S., Coache, C. D., & Roux, R. J. (2020). National electrical code handbook. Quincy, Mass: National Fire Protection Association.
Written By:
Anthony Chan
Sr. Electrical Designer