If It Ain't Broke ...

In the March 2012 Electrical Contractor, I mentioned the increased number of receptacles in patient bed locations with a minimum of 14 receptacles in a Category 1 critical-care area and 36 receptacles in a Category 1 operating room for the 2014 National Electrical Code (NEC), based on changes in the 2012 NFPA 99, the Standard for Health Care Facilities. However, I did not mention the removal of any reference to Article 700 and the term “emergency system” from definitions in 517.2 and from Part III of Article 517. Some readers have questioned the justification for this change, and it deserves some attention. Underlined text shows additions; strike-through text shows deletions. 

A revised definition of a “critical branch” in 517.2 was provided by Proposal 15-12 for the 2014 NEC as follows: “A system of subsystem of the emergency system consisting of feeders and branch circuits supplying power for energy to task illumination, fixed equipment, select receptacles, and special power circuits, and selected receptacles serving areas and functions related to patient care and that are connected to alternate power sources by one or more transfer switches during interruption of normal power source” [NFPA 99 3.3.30]. Deleting the phrase “subsystem of the emergency system” in this definition is the first step in removing any reference to Article 700 and emergency systems from wiring of healthcare systems. The substantiation given by the NFPA 99 Electrical Committee for the removal of the emergency system from the essential electrical system for hospitals was “to coordinate with the changes in NFPA 99. As a result of the August 10, 2011 Standards Council Decision (Final), D#11-7 ... , regarding the scoping issues of electrical requirements in NFPA 99, Health Care Facilities Code, coordination of the electrical requirements is needed between the NEC and NFPA 99. An excerpt from D#11-7 states: ‘The Council believes that the distinction between performance requirements and installation requirements is reasonably clear and the Council reiterates that without deciding in advance what the Council would do regarding specific jurisdictional issues relating to this topic, the Council considers the guidance [from the previous task group] to be Useful’. (See the Standards Council Minute-Item 10-3-21, March 2010). In this decision, the Council has concluded that selective coordination (cascading outages) properly falls within the jurisdiction of NFPA 99. The NEC project should proceed, as part of its standards development activities, to harmonize the NEC with the relevant provisions of NFPA 99.”

The text for 517.26 in the 2011 and previous editions of the NEC involved the requirement of the essential electrical system, such as the life safety and the critical branch, to use Article 700, except as amended by Article 517. For the 2014 NEC, Proposal 15-48 was submitted by the NFPA 99 Technical Committee on Electrical Systems to revise 517.26 as follows: “Application of Other Articles. The life safety branch of the essential electrical system shall meet the requirements of Article 700, except as amended by Article 517. “Informational Note No. 2: For additional information see 517.30 and NFPA 99, Chapter 6.”

The substantiation for this comment stated, “the critical branch of the emergency power supply system must comply with Article 700; newly installed generators in health care facilities will be required to be substantially oversized.”

Section 700.5(A) states, “Capacity and Rating. An emergency system shall have adequate capacity and rating for all loads to be operated simultaneously. The emergency system equipment shall be suitable for the maximum available fault current at its terminals.” The generator set(s) shall have sufficient capacity and proper rating to meet the maximum actual demand likely to be produced by the connected load of the essential electrical system(s) at any one time. The critical branch is made up of many patient- and equipment-related loads. These loads, unlike those for illumination, panic control, life safety, etc. are not intended to all function at the same time. The list is long and has been provided so the Standards Council members can see why requiring all loads to be operated simultaneously would cause the generator to be substantially oversized for the application.”

However, the NFPA 99 Electrical Committee did not take into consideration the existing text in 517.30(D): “The sizing requirements in 700.4 and 701.4 shall not apply to hospital generator set(s).” Both the NFPA 99 Electrical Committee and CMP-15 may have overlooked NEC 517.30(D) as a solution to their concerns, and a possible review by CMP-15 at the NEC comment meeting would be beneficial to the 2014 NEC while maintaining compliance with NFPA 99.

About the Author

Mark C. Ode

Fire/Life Safety Columnist and Code Contributor
Mark C. Ode is a lead engineering associate for Energy & Power Technologies at Underwriters Laboratories Inc. and can be reached at 919.949.2576 and Mark.C.Ode@ul.com .

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.