Type MC and Type MI cable shall have an outer metal

armor or sheath that is identified as an acceptable grounding return path. 517-14. Panelboard Bonding. The equipment grounding terminal busses of the normal and essential branch-circuit panelboards serving the same individual patient vicinity shall be bonded together with an insulated continuous copper conductor not smaller than No. 10. Where more than two 70-536 NATIONAL ELECTRICAL CODE (2) panels serve the same location, this conductor shall be continuous from panel to panel, but shall be permitted to be broken in order to terminate on the ground bus in each panel. 517-16. Receptacles with Insulated Grounding Terminals. Receptacles with insulated grounding terminals as permitted in Section 250-74, Exception No. 4 shall be identified; such identification shall be visible after installation. (FPN): Caution is important in specifying such a system with receptacles having insulated grounding terminals, since the grounding impedance is controlled only by the grounding conductors and does not benefit functionally from any parallel grounding paths. 517-17. Ground-Fault Protection. (a) Feeders. Where ground-fault protection is provided for operation of the service disconnecting means or feeder disconnecting means as specified by Sections 230-95 or 215-10, an additional step of ground-fault protection shall be provided in the next level of feeder disconnecting means downstream toward the load. Such protection shall consist of overcurrent devices and current transformers or other equivalent protective equipment that shall cause the feeder disconnecting means to open. (FPN): The additional levels of ground-fault protection required by Section 517-17(a) are not intended: a. On the load side of an essential electrical system transfer switch, or b. Between the on-site generating unit(s) described in Section 517-35(b) and the essential electrical system transfer switch(es), or c. On electrical systems that are not solidly grounded wye systems with greater than 150 volts to ground, but not exceeding 600 volts phase-to-phase. (b) Selectivity. Ground-fault protection for operation of the service and feeder disconnecting means shall be fully selective such that the feeder device and not the service device shall open on ground faults on the load side of the feeder device. A six-cycle minimum separation between the service and feeder ground-fault tripping bands shall be provided. Operating time of the disconnecting devices shall be considered in selecting the time spread between these two bands to achieve 100 percent selectivity. (FPN): See Section 230-95, Fine Print Note, for transfer of alternate source where ground-fault protection is applied. (c) Testing. When equipment ground-fault protection is first installed, each level shall be performance tested to ensure compliance with (b) above. 517-18. General Care Areas. (a) Patient Bed Location Branch Circuits. Each patient bed location shall be supplied by at least two branch circuits, at least one of which originates in a normal system panelboard; all branch circuits from the normal system shall originate in the same panelboard. ARTICLE 517 - HEALTH CARE FACILITIES 70-537 Exception No. 1: Branch circuits serving only special-purpose outlets or receptacles, such as portable X-ray outlets, shall not be required to be served from the same distribution panel or panels. Exception No. 2: Clinics, medical and dental offices, and outpatient facilities; psychiatric, substance abuse, and rehabilitation hospitals; nursing homes and residential custodial care facilities meeting the requirements of the exceptions to Section 517-10. (b) Patient Bed Location Receptacles. Each patient bed location shall be provided with a minimum of four receptacles. They shall be permitted to be of the single or duplex types or a combination of both. All receptacles, whether four or more, shall be listed "hospital grade" and so identified. The requirement that the receptacles be listed "hospital grade" and so identified shall become effective January 1, 1993. Each receptacle shall be grounded by means of an insulated copper conductor sized in accordance with Table 250-95. Exception No. 1: Psychiatric, substance abuse, and rehabilitation hospitals meeting the requirements of the exceptions to Section 517-10. Exception No. 2: Psychiatric security rooms shall not be required to have receptacle outlets installed in the room. (FPN): It is not intended that there be a total, immediate replacement of existing non-"hospital grade" receptacles. It is intended, however, that non-"hospital grade" receptacles be replaced with "hospital grade" receptacles upon modification of use, renovation, or as existing receptacles need replacement. (c) Pediatric Locations. Fifteen- and 20-ampere, 125-volt receptacles intended to supply patient care areas of pediatric wards, rooms, or areas shall be tamper resistant. For the purpose of this section, a tamper resistant receptacle is a receptacle that, by its construction, limits improper access to its energized contacts. 517-19. Critical Care Areas. (a) Patient Bed Location Branch Circuits. Each patient bed location shall be supplied by at least two branch circuits, one or more from the emergency system and one or more circuits from the normal system. At least one branch circuit from the emergency system shall supply an outlet(s) only at that bed location. All branch circuits from the normal system shall be from a single panelboard. Emergency system receptacles shall be identified and shall also indicate the panelboard and circuit number supplying them. Exception: Branch circuits serving only special-purpose receptacles or equipment in critical care areas shall be permitted to be served by other panelboards. (b) Patient Bed Location Receptacles. Each patient bed location shall be provided with a minimum of six receptacles. They may be of the single or duplex types or a combination of both. All receptacles, whether six or more, shall be listed "hospital grade" and so identified; each receptacle shall be grounded to the reference grounding point by means of an insulated copper equipment grounding conductor. 70-538 NATIONAL ELECTRICAL CODE (c) Patient Vicinity Grounding and Bonding (Optional). A patient vicinity shall be permitted to have a patient equipment grounding point. The patient equipment grounding point, where supplied, shall be permitted to contain one or more jacks listed for the purpose. An equipment bonding jumper, not smaller than No. 10, shall be used to connect the grounding terminal of all grounding-type receptacles to the patient equipment grounding point. The bonding conductor shall be permitted to be arranged centrically or looped as convenient. (FPN): Where there is no patient equipment grounding point, it is important that the distance between the reference grounding point and the patient vicinity be as short as possible to minimize any potential differences. (d) Panelboard Grounding. Where a grounded electrical distribution system is used, and metal feeder raceway or Type MC or MI cable is installed, grounding of a panelboard or switchboard shall be assured by one of the following means at each termination or junction point of the raceway or Type MC or MI cable: (1) A grounding bushing and a continuous copper bonding jumper, sized in accordance with Section 250-95, with the bonding jumper connected to the junction enclosure or the ground bus of the panel. (2) Connection of feeder raceways or Type MC or MI cable to threaded hubs or bosses on terminating enclosures. (3) Other approved devices, such as bonding-type locknuts or bushings. (e) Additional Protective Techniques in Critical Care Areas (Optional). Isolated power systems shall be permitted to be used for critical care areas, and, if used, the isolated power system equipment shall be listed for the purpose and the system so designed and installed that it meets the provisions and is in accordance with Section 517-160. Exception: The audible and visual indicators of the line isolation monitor shall be permitted to be located at the nursing station for the area being served. (f) Isolated Power System Grounding. Where an isolated ungrounded power source is used and limits the first-fault current to a low magnitude, the grounding conductor associated with the secondary circuit shall be permitted to be run outside of the enclosure of the power conductors in the same circuit. (FPN): Although it is permitted to run the grounding conductor outside of the conduit, it is safer to run it with the power conductors to provide better protection in case of a second ground fault. (g) Special-Purpose Receptacle Grounding. The equipment grounding conductor for special-purpose receptacles such as the operation of mobile X-ray equipment shall be extended to the reference grounding points of branch circuits for all locations likely to be served from such receptacles. Where such a circuit is served from an isolated ungrounded system, the grounding conductor shall not be required to be run with the power conductors; however, the equipment grounding terminal of the specialpurpose receptacle shall be connected to the reference grounding point. ARTICLE 517 - HEALTH CARE FACILITIES 70-539 517-20. Wet Locations. (a) All receptacles and fixed equipment within the area of the wet location shall have ground-fault circuit-interrupter protection for personnel if interruption of power under fault conditions can be tolerated, or be served by an isolated power system if such interruption cannot be tolerated. Exception: Branch circuits supplying only listed, fixed, therapeutic and diagnostic equipment shall be permitted to be supplied from a normal grounded service, single- or 3-phase system, provided: a. Wiring for grounded and isolated circuits does not occupy the same raceway, and b. All conductive surfaces of the equipment are grounded. (b) Where an isolated power system is utilized, the equipment shall be listed for the purpose and installed so that it meets the provisions of, and is in accordance with, Section 517-160. (FPN): For requirements for installation of therapeutic pools and tubs, see Part F of Article 680. C. Essential Electrical System 517-25.* Scope. The essential electrical system for these facilities shall comprise a system capable of supplying a limited amount of lighting and power service which is considered essential for life safety and orderly cessation of procedures during the time normal electrical service is interrupted for any reason. This includes clinics, medical and dental offices, outpatient facilities, nursing homes, limited care facilities, hospitals, and other health care facilities serving patients. (FPN): For information as to the need for an essential electrical system, see Health Care Facilities, NFPA 99-1990 (ANSI). 517-30. Essential Electrical Systems For Hospitals. (a) Applicability. The requirements of Part C, Sections 517-30 through 517-35, shall apply to hospitals where an essential electrical system is required. (FPN No. 1): For performance, maintenance, and testing requirements of essential electrical systems in hospitals, see Health Care Facilities, NFPA 99-1990 (ANSI). For installation of centrifugal fire pumps, see Installation of Centrifugal Fire Pumps, NFPA 20-1990 (ANSI). (FPN No. 2): For additional information, see Health Care Facilities, NFPA 99-1990 (ANSI). (b) General. (1)* Essential electrical systems for hospitals shall be comprised of two separate systems capable of supplying a limited amount of lighting and power service which is considered essential for life safety and effective hospital operation during the time the normal electrical service is interrupted for any reason. These two systems shall be the emergency system and the equipment system. (2)* The emergency system shall be limited to circuits essential to life safety and critical patient care. These are designated the life safety branch and the critical branch. 70-540 NATIONAL ELECTRICAL CODE (3)* The equipment system shall supply major electric equipment necessary for patient care and basic hospital operation. (4)x The number of transfer switches to be used shall be based upon reliability, design, and load considerations. Each branch of the essential electrical system shall be served by one or more transfer switches as shown in Diagrams 517-30(1) and 517-30(2). One transfer switch shall be permitted to serve one or more branches or systems in a facility with a maximum demand on the essential electrical system of 150 kVA as shown in Diagram 517-30(3). (FPN): See Health Care Facilities, NFPA 99-1990 (ANSI): Section 3-5.1.2.2(a), Transfer Switch Operation Type I; Section 3-4.2.1.4, Automatic Transfer Switch Features; and Section 3-4.2.1.6, Nonautomatic Transfer Device Features. Small electrical system-hospitals Normal sources Alternate source G SE Nonessential loads Equipment systems SE Service entrance Life safety Critical Overcurrent protection branch branch Automatic switching equipment Essential electrical system Delayed automatic switching equipment Transformer G Generator Diagram 517-30(1) Typical large electrical system-hospitals Normal source Normal sources Alternate source G SE DSE ... Nonessential loads Critical Equipment branch system Life safety branch ARTICLE 517 - HEALTH CARE FACILITIES Transformer Overcurrent protection Essential electrical system G Generator Automatic switching equipment SE Service entrance Delayed automatic switching means DSE Double-ended service with normally open Manual switching means Diagram 517-30(2) 70-541 70-542 NATIONAL ELECTRICAL CODE Small electrical system-hospitals (single transfer switch) Normal sources Alternate sources G SE Nonessential loads Essential electrical system (150 kVA or less) SE Service entrance Overcurrent protection Automatic switching ao equipment Transformer G Generator Diagram 517-30 (3) ARTICLE 517 - HEALTH CARE FACILITIES 70-543 (c) Wiring Requirements. (1) Separation from Other Circuits. The life safety branch and critical branch of the emergency system shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceways, boxes, or cabinets with each other or other wiring, except as follows: a. In transfer switches, b. In exit or emergency lighting fixtures supplied from two sources, or c. In a common junction box attached to exit or emergency lighting fixtures supplied from two sources. The wiring of the equipment system shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits that are not part of the emergency system. (2) Isolated Power Systems. Where isolated power systems are installed in any of the areas in Sections 517-33(a)(1) and (a)(2), each system shall be supplied by an individual circuit serving no other load. (3) Mechanical Protection of the Emergency System. The wiring of the emergency system of a hospital shall be mechanically protected by installation in metal raceways. Exception No. 1: Flexible power cords of appliances, or other utilization equipment, connected to the emergency system shall not be required to be enclosed in raceways. Exception No. 2: Secondary circuits of transformer-powered communication or signaling systems shall not be required to be enclosed in raceways unless otherwise specified by Chapter 7 or 8. Exception No. 3: Schedule 80 rigid nonmetallic conduit shall be permitted except for branch circuits serving patient care areas. Exception No. 4: Where encased in not less than 2 inches (50.8 mm) of concrete, Schedule 40 PVC shall be permitted except for branch circuits serving patient care areas. (FPN): See Section 517-13(b) for additional grounding requirements in patient care areas. (d) Capacity of Systems. The essential electrical system shall have adequate capacity to meet the demand for the operation of all functions and equipment to be served by each system and branch. 517-31.* Emergency System. Those functions of patient care depending on lighting or appliances that are connected to the emergency system shall be divided into two mandatory branches: the life safety branch and the critical branch, described in Sections 517-32 and 517-33. The branches of the emergency system shall be installed and connected to the alternate power source so that all functions specified herein for the emergency system shall be automatically restored to operation within 10 seconds after interruption of the normal source. 517-32.* Life Safety Branch. No function other than those listed in (a) through (f) shall be connected to the life safety branch. The life safety branch of the emergency system shall supply power for the following lighting, receptacles, and equipment: 70-544 NATIONAL ELECTRICAL CODE (a) Illumination of Means of Egress. Illumination of means of egress, such as lighting required for corridors, passageways, stairways and landings at exit doors, and all necessary ways of approach to exits. Switching arrangements to transfer patient corridor lighting in hospitals from general illumination circuits to night illumination circuits shall be permitted provided only one of two circuits can be selected, and both circuits cannot be extinguished at the same time. (FPN): See Life Safety Code, NFPA 101-1991 (ANSI), Section 5-10. (b) Exit Signs. Exit signs and exit directional signs. (FPN): See Life Safety Code, NFPA 101-1991 (ANSI), Section 5-11. (c) Alarm and Alerting Systems. Alarm and alerting systems including: (1) Fire alarms. (FPN): See Life Safety Code, NFPA 101-1991 (ANSI), Sections 12-1 and 12-2. (4) Alarms required for systems used for the piping of nonflammable medical gases. (FPN): See Health Care Facilities, NFPA 99-1990 (ANSI), Section 12-3.4.1. (d) Communication Systems. Hospital communication systems, where used for issuing instructions during emergency conditions. (e) Generator Set Location. Task illumination battery charger for emergency battery-powered lighting unit(s) and selected receptacles at the generator set location. (f) Elevators. Elevator cab lighting, control, communication, and signal systems. 517-33.* Critical Branch. (a) Task Illumination and Selected Receptacles. The critical branch of the emergency system shall supply power for task illumination, fixed equipment, selected receptacles, and special power circuits serving the following areas and functions related to patient care. (1) Anesthetizing locations - task illumination, all receptacles and fixed equipment. (2) The isolated power systems in special environments. (3) Patient care areas - task illumination and selected receptacles in: a. Infant nurseries, b. Medication preparation areas, c. Pharmacy dispensing areas, d. Selected acute nursing areas, e. Psychiatric bed areas (omit receptacles), f. Ward treatment rooms, and g. Nurses' stations (unless adequately lighted by corridor luminaires). (4) Additional specialized patient care task illumination and receptacles, where needed. ARTICLE 517 - HEALTH CARE FACILITIES 70-545 (5) Nurse call systems. (6) Blood, bone, and tissue banks. (7) Telephone equipment room and closets. (8) Task illumination, selected receptacles, and selected power circuits for: a. General care beds (at least one duplex receptacle per patient bedroom), b. Angiographic labs, c. Cardiac catheterization labs, d. Coronary care units, e. Hemodialysis rooms or areas, f. Emergency room treatment areas (selected), g. Human physiology labs, h. Intensive care units, and i. Postoperative recovery rooms (selected). (9) Additional task illumination, receptacles, and selected power circuits needed for effective hospital operation. Single-phase fractional horsepower exhaust fan motors that are interlocked with 3-phase motors on the equipment shall be permitted to be connected to the critical branch. (b) Subdivision of the Critical Branch. It shall be permitted to subdivide the critical branch into two or more branches. (FPN): It is important to analyze the consequences of supplying an area with only critical care branch power when failure occurs between the area and the transfer switch. Some proportion of normal and critical power, or critical power from separate transfer switches, may be appropriate. 517-34.* Equipment System Connection to Alternate Power Source. The equipment system shall be installed and connected to the alternate source, such that the equipment described in Section 517-34(a) is automatically restored to operation at appropriate time-lag intervals following the energizing of the emergency system. Its arrangement shall also provide for the subsequent connection of equipment described in Section 517-34(b). (a)* Equipment for Delayed Automatic Connection. The following equipment shall be arranged for delayed automatic connection to the alternate power source: (1) Central suction systems serving medical and surgical functions, including controls. Such suction systems shall be permitted on the critical branch. (2) Sump pumps and other equipment required to operate for the safety of major apparatus, including associated control systems and alarms. (3) Compressed air systems serving medical and surgical functions, including controls. (FPN): The above equipment may be arranged for sequential delayed automatic connection to the alternate power source to prevent overloading the generator where engineering studies indicate it is necessary. (b)* Equipment for Delayed Automatic or Manual Connection. The following equipment shall be arranged for either delayed automatic or manual connection to the alternate power source: 70-546 NATIONAL ELECTRICAL CODE (1) Heating equipment to provide heating for operating, delivery, labor, recovery, intensive care, coronary care, nurseries, infection/ isolation rooms, emergency treatment spaces, and general patient rooms. Exception: Heating of general patient rooms and infection/isolation rooms during disruption of the normal source shall not be required under any of the following conditions: a. The outside design temperature is higher than +20°F (-6.7°C), or b. The outside design temperature is lower than +20°F (-6.7°C) and where a selected room(s) is provided for the needs of all confined patients, then only such room(s) need be heated, or c. The facility is served by a dual source of normal power as described in Section 517-35(c), Fine Print Note. (FPN): The design temperature is based on the 97½ percent design value as shown in Chapter 24 of the ASHRAE Handbook of Fundamentals (1985). (2) Elevator(s) selected to provide service to patient, surgical, obstetrical, and ground floors during interruption of normal power. In instances where interruption of normal power would result in other elevators stopping between floors, throw-over facilities shall be provided to allow the temporary operation of any elevator for the release of patients or other persons who may be confined between floors. (3) Supply, return, and exhaust ventilating systems for surgical and obstetrical delivery suites, intensive care, coronary care, nurseries, infection/isolation rooms, emergency treatment spaces, and exhaust fans for laboratory fume hoods, nuclear medicine areas where radioactive material is used, ethylene oxide evacuation, and anesthesia evacuation. (4) Hyperbaric facilities. (5) Hypobaric facilities. (6) Automatically operated doors. (7) Minimal electrically heated autoclaving equipment shall be permitted to be arranged for either automatic or manual connection to the alternate source. (8) Other selected equipment shall be permitted to be served by the equipment system. 517-35. Sources of Power. (a)* Two Independent Sources of Power. Essential electrical systems shall have a minimum of two independent sources of power: a normal source generally supplying the entire electrical system, and one or more alternate sources for use when the normal source is interrupted. (b)* Alternate Source of Power. The alternate source of power shall be a generator(s) driven by some form of prime mover(s), and located on the premises. Exception: Where the normal source consists of generating units on the permises, the alternate source shall be either another generating set, or an external utility service. (c) Location of Essential Electrical System Components. Careful consideration shall be given to the location of the spaces housing the compo- ARTICLE 517 - HEALTH CARE FACILITIES 70-547 nents of the essential electrical system to minimize interruptions caused by natural forces common to the area (e.g., storms, floods, earthquakes, or hazards created by adjoining structures or activities). Consideration shall also be given to the possible interruption of normal electrical services resulting from similar causes as well as possible disruption of normal electrical service due to internal wiring and equipment failures. (FPN): Facilities whose normal source of power is supplied by two or more separate central station-fed services experience greater than normal electrical service reliability than those with only a single feed. Such a dual source of normal power consists of two or more electrical services fed from separate generator sets or a utility distribution network having multiple power input sources and arranged to provide mechanical and electrical separation so that a fault between the facility and the generating sources will not likely cause an interrupution of more than one of the facility service feeders. 517-40. Essential Electrical Systems for Nursing Homes and Limited Care Facilities. (a) Applicability. The requirements of Part C, Sections 517-40(c) through 517-44, shall apply to nursing homes and limited care facilities. Facilities that fulfill Section 517-10, Exception No. 3 shall be exempt from these requirements. (b) Inpatient Hospital Care Facilities. Nursing homes and limited care facilities that provide inpatient hospital care shall comply with the requirements of Part C, Sections 517-30 through 517-35. (c) Facilities Contiguous with Hospitals. Nursing homes and limited care facilities that are contiguous with a hospital shall be permitted to have their essential electrical systems supplied by that of the hospital. (FPN): For performance, maintenance, and testing requirements of essential electrical systems in nursing homes and limited care facilities, see Health Care Facilities, NFPA 99-1990 (ANSI). 517-41. Essential Electrical Systems. (a)* General. Essential electrical systems for nursing homes and limited care facilities shall be comprised of two separate branches capable of supplying a limited amount of lighting and power service which is considered essential for the protection of life safety and effective operation of the institution during the time normal electrical service is interrupted for any reason. These two separate branches shall be the life safety branch and the critical branch. (b)* Transfer Switches. The number of transfer switches to be used shall be based upon reliability, design, and load considerations. Each branch of the essential electrical system shall be served by one or more transfer switches as shown in Diagrams 517-41(1) and 517-41(2). One transfer switch shall be permitted to serve one or more branches or systems in a facility with a maximum demand on the essential electrical system of 150 kVa as shown in Diagram 517-41(3). (FPN): See Health Care Facilities, NFPA 99-1990 (ANSI): Section 3-5.1.2.2(b), Transfer Switch Operation Type II; Section 3-4.2.1.4, Automatic Transfer Switch Features; and Section 3-4.2.1.6, Nonautomatic Transfer Device Features. 70-548 NATIONAL ELECTRICAL CODE Small electrical system-Nursing homes and residential custodial care facilities Normal sources Alternate source G SE Nonessential loads Life safety Critical branch branch Essential electrical system SE Service entrance Overcurrent protection Automatic switching equipment Delayed automatic switching equipment Transformer G Generator Diagram 517-41(1) Typical large electrical system-Nursing homes and residential custodial care facilities Normal source Alternate source G SE Nonessential loads Transformer Life safety branch Critical branch heating G Generator Critical branch Critical branch patients ARTICLE 517 - HEALTH CARE FACILITIES sump pumps-alarms SE Service entrance Overcurrent protection Essential electrical system Automatic switching equipment Delayed automatic switching equipment Manual switching equipment Diagram 517-41(2) 70-549 70-550 NATIONAL ELECTRICAL CODE Small electrical system-Nursing homes and residential custodial care facilities (single transfer switch) Normal sources Alternate source G SE Nonessential loads Essential electrical system (150 kVa or less) SE Service entrance Overcurrent protection Automatic switching equipment Transformer G Generator Diagram 517-41(3) ARTICLE 517 - HEALTH CARE FACILITIES 70-551 (c) Capacity of System. The essential electrical system shall have adequate capacity to meet the demand for the operation of all functions and equipment to be served by each branch at one time. (d) Separation from Other Circuits. The life safety branch shall be kept entirely independent of all other wiring and equipment and shall not enter the same raceways, boxes, or cabinets with other wiring except as follows: (1) In transfer switches, (2) In exit or emergency lighting fixtures supplied from two sources, or (3) In a common junction box attached to exit or emergency lighting fixtures supplied from two sources. The wiring of the critical branch shall be permitted to occupy the same raceways, boxes, or cabinets of other circuits that are not part of the life safety branch. 517-42.* Automatic Connection to Life Safety Branch. The life safety branch shall be so installed and connected to the alternate source of power that all functions specified herein shall be automatically restored to operation within 10 seconds after the interruption of the normal source. No function other than those listed in (a) through (g) shall be connected to the life safety branch. The life safety branch shall supply power for the following lighting, receptacles, and equipment: (FPN): The life safety branch is called the emergency system in Health Care Facilities, NFPA 99-1990 (ANSI). (a) Illumination of Means of Egress. Illumination of means of egress as is necessary for corridors, passageways, stairways, landings, and exit doors and all ways of approach to exits. Switching arrangement to transfer patient corridor lighting from general illumination circuits shall be permitted providing only one of two circuits can be selected, and both circuits cannot be extinguished at the same time. (FPN): See Life Safety Code, NFPA 101-1991 (ANSI), Section 5-10. (b) Exit Signs. Exit signs and exit directional signs. (FPN): See Life Safety Code, NFPA 101-1991 (ANSI), Section 5-11. (c) Alarm and Alerting Systems. Alarm and alerting systems, including: (1) Fire alarms. (FPN): See Life Safety Code, NFPA 101-1991 (ANSI), Sections 7-6, 12-3.4, and 12-3.5. (2) Alarms required for systems used for the piping of nonflammable medical gases. (FPN): See Health Care Facilities, NFPA 99-1990 (ANSI), Section 16-3.4.1. (d) Communications Systems. Communications systems, where used for issuing instructions during emergency conditions. (e) Dining and Recreation Areas. Sufficient lighting in dining and recreation areas to provide illumination to exit ways. (f) Generator Set Location. Task illumination and selected receptacles in the generator set location. (g) Elevators. Elevator cab lighting, control, communication, and signal systems. 70-552 NATIONAL ELECTRICAL CODE 517-43.* Connection to Critical Branch. The critical branch shall be so installed and connected to the alternate power source that the equipment listed in Section 517-43(a) shall be automatically restored to operation at appropriate time-lag intervals following the restoration of the life safety branch to operation. Its arrangement shall also provide for the additional connection of equipment listed in Section 517-43(b) by either delayed automatic or manual operation. (a) Delayed Automatic Connection. The following equipment shall be connected to the critical branch and shall be arranged for delayed automatic connection to the alternate power source: (1) Patient care areas - task illumination and selected receptacles in: a. Medication preparation areas. b. Pharmacy dispensing areas. c. Nurses' stations (unless adequately lighted by corridor luminaires). (2) Sump pumps and other equipment required to operate for the safety of major apparatus and associated control systems and alarms. (b) Delayed Automatic or Manual Connection. The following equipment shall be connected to the critical branch and shall be arranged for either delayed automatic or manual connection to the alternate power source: (1) Heating equipment to provide heating for patient rooms. Exception: Heating of general patient rooms during disruption of the normal source shall not be required under any of the following conditions: a. The outside design temperature is higher than +20°F (-6.7°C), or b. The outside design temperature is lower than +20°F (-6.7°C) and where a selected room(s) is provided for the needs of all confined patients, then only such room(s) need be heated, or c. The facility is served by a dual source of normal power as described in Section 517-44(c), Fine Print Note. (FPN): The outside design temperature is based on the 97½ percent design values as shown in Chapter 24 of the ASHRAE Handbook of Fundamentals (1985). (2) Elevator Service. In instances where disruption of power would result in elevators stopping between floors, throw-over facilities shall be provided to allow the temporary operation of any elevator for the release of passengers. For elevator cab lighting, control, and signal system requirements, see Section 517-42(g). (3) Additional illumination, receptacles, and equipment shall be permitted to be connected only to the critical branch. 517-44. Sources of Power. (a)* Two Independent Sources of Power. Essential electrical systems shall have a minimum of two independent sources of power: a normal source generally supplying the entire electrical system, and one or more alternate sources for use when the normal source is interrupted. (b)* Alternate Source of Power. The alternate source of power shall be a generator(s) driven by some form of prime mover(s), and located on the premises. ARTICLE 517 - HEALTH CARE FACILITIES 70-553 Exception No. 1: Where the normal source consists of generating units on the premises, the alternate source shall be either another generator set, or an external utility service. Exception No. 2: Nursing homes or residential custodial care facilities meeting the requirements of Section 517-10, Exception No. 3 shall be per- I mitted to use a battery system or self-contained battery integral with the equipment. (c) Location of Essential Electrical System Components. Careful consideration shall be given to the location of the spaces housing the components of the essential electrical system to minimize interruptions caused by natural forces common to the area (e.g., storms, floods, earthquakes, or hazards created by adjoining structures or activities). Consideration shall also be given to the possible interruption of normal electrical services resulting from similar causes as well as possible disruption of normal electrical service due to internal wiring and equipment failures. (FPN): Facilities whose normal source of power is supplied by two or more separate central station-fed services experience greater than normal electrical service reliability than those with only a single feed. Such a dual source of normal power consists of two or more electrical services fed from separate generator sets or a utility distribution network having multiple power input sources and arranged to provide mechanical and electrical separation so that a fault between the facility and the generating sources will not likely cause an interruption of more than one of the facility service feeders. 517-50. Essential Electrical Systems for Clinics, Medical and Dental Offices, Outpatient Facilities, and Other Health Care Facilities Not Covered in Sections 517-30 and 517-40. (a)* Applicability. The requirements of this section shall apply to those health care facilities described in Section 517-50, and in which: (1) Inhalation anesthetics are administered in any concentration to patients, or (2) Patients require electrical life-support equipment. (b)* Connections. The essential electrical system shall supply power for: (1) Task illumination which is related to the safety of life and which is necessary for the safe cessation of procedures in progress. (2) All anesthesia and resuscitative equipment used in areas where inhalation anesthetics are administered to patients, including alarm and alerting devices. (FPN): See Health Care Facilities, NFPA 99-1990 (ANSI), Sections 13-3.4.1, 14-3.4.1, and 15-3.4.1. (3) All electrical life-support equipment in areas where procedures are performed that require such equipment for the support of the patient's life. (c) Alternate Source of Power. (1)* Power Source. The alternate source of power for the system shall be specifically designed for this purpose and shall be either a generator, battery system, or self-contained battery integral with the equipment. 70-554 NATIONAL ELECTRICAL CODE (2)* System Capacity. The alternate source of power shall be separate and independent of the normal source and shall have a capacity to sustain its connected loads for a minimum of 1½ hours after loss of the normal source. (3)* System Operation. The system shall be so arranged that, in the event of a failure of the normal power source, the alternate source of power shall be automatically connected to the load within 10 seconds. (FPN): See Health Care Facilities, NFPA 99-1990 (ANSI), Sections 3-5.1.2.2(c), Transfer Switch Operation for Type III with Generator Sets, and 3-5.1.2.2(d), Transfer Switch Operation for Type III with Battery Systems. D. Inhalation Anesthetizing Locations (FPN): For further information regarding safeguards for anesthetizing locations, see Health Care Facilities, NFPA 99-1990 (ANSI). 517-60. Anesthetizing Location Classification. (FPN): If either of the following anesthetizing locations is designated a wet location, refer to Section 517-20. (a) Hazardous (Classified) Location. (1)* In a location where flammable anesthetics are employed, the entire area shall be considered to be a Class I, Division 1 location which shall extend upward to a level 5 feet (1.52 above the floor. The remaining volume up to the structural ceiling is considered to be above a hazardous (classified) location. (2) Any room or location in which flammable anesthetics or volatile flammable disinfecting agents are stored shall be considered to be a Class I, Division 1 location from floor to ceiling. (b) Other-than-Hazardous (Classified) Location. Any inhalation anesthetizing location designated for the exclusive use of nonflammable anesthetizing agents shall be considered to be an other-than-hazardous (classified) location. 517-61. Wiring and Equipment. (a) Within Hazardous Anesthetizing Locations. (1)* Except as permitted in Section 517-160, each power circuit within, or partially within, a flammable anesthetizing location as referred to in Section 517-60 shall be isolated from any distribution system by the use of an isolated power system. (2) Isolated power system equipment shall be listed for the purpose and the system so designed and installed that it meets the provisions and is in accordance with Part G. (3)* In hazardous (classified) location(s) referred to in Section 517-60, all fixed wiring and equipment, and all portable equipment, including lamps and other utilization equipment, operating at more than 10 volts between conductors shall comply with the requirements of Sections 501-1 through 501-15 and Sections 501-16(a) and (b) for Class I, Division 1 locations. All such equipment shall be specifically approved for the hazardous atmospheres involved. ARTICLE 517 - HEALTH CARE FACILITIES 70-555 (4) Where a box, fitting, or enclosure is partially, but not entirely, within a hazardous (classified) location(s), the hazardous (classified) location(s) shall be considered to be extended to include the entire box, fitting, or enclosure. (5) Receptacles and attachment plugs in hazardous (classified) location(s) shall be listed for use in Class I, Group C hazardous (classified) locations and shall have provision for the connection of a grounding conductor. (6) Flexible cords used in hazardous areas for connection to portable utilization equipment, including lamps operating at more than 8 volts between conductors, shall be of a type approved for extra-hard usage in accordance with Table 400-4 and shall include an additional conductor for grounding. (7) A storage device for the flexible cord shall be provided and shall not subject the cord to bending at a radius of less than 3 inches (76 mm). (b) Above Hazardous Anesthetizing Locations. (1) Wiring above a hazardous area referred to in Section 517-60 shall be installed in rigid metal conduit, electrical metallic tubing, intermediate metal conduit, Type MI cable, or Type MC cable that employs a continuous, gas/vapor-tight metal sheath. (2) Installed equipment that may produce arcs, sparks, or particles of hot metal, such as lamps and lampholders for fixed lighting, cutouts, switches, generators, motors, or other equipment having make-and-break or sliding contacts, shall be of the totally enclosed type or so constructed as to prevent escape of sparks or hot metal particles. Exception: Wall-mounted receptacles installed above the hazardous area in flammable anesthetizing locations shall not be required to be totally enclosed or have openings guarded or screened to prevent dispersion of particles. (3) Surgical and other lighting fixtures shall conform to Section 501-9(b). Exception No. 1: The surface temperature limitations set forth in Section 501-9(b)(2) shall not apply. Exception No. 2: Integral or pendant switches that are located above and cannot be lowered into the hazardous (classified) location(s) shall not be required to be explosionproof. (4) Approved seals shall be provided in conformance with Section 501-5, and Section 501-5(a)(4) shall apply to horizontal as well as to vertical boundaries of the defined hazardous (classified) locations. (5) Receptacles and attachment plugs located above hazardous anesthetizing locations shall be listed for hospital use for services of prescribed voltage, frequency, rating, and number of conductors with provision for the connection of the grounding conductor. This requirement shall apply to attachment plugs and receptacles of the 2-pole, 3-wire grounding type for single-phase 120-volt, nominal, ac service. (6) Plugs and receptacles rated 250-volt, for connection of 50-ampere, and 60-ampere ac medical equipment for use above hazardous (classified) 70-556 NATIONAL ELECTRICAL CODE locations shall be so arranged that the 60-ampere receptacle will accept either the 50-ampere or the 60-ampere plug. Fifty-ampere receptacles shall be designed so as not to accept the 60-ampere attachment plug. The plugs shall be of the 2-pole, 3-wire design with a third contact connecting to the insulated (green or green with yellow stripe) equipment grounding conductor of the electrical system. (c) Other-than-Hazardous Anesthetizing Locations. (1) Wiring serving other-than-hazardous (classified) locations, as defined in Section 517-60, shall be installed in a metal raceway system or cable assembly. The metal raceway system, or cable armor or sheath assembly, shall qualify as an equipment grounding return path in accordance with Section 250-91(b). Type MC and Type MI cable shall have an outer metal armor or sheath that is identified as an acceptable grounding return path. Exception: Pendant receptacle constructions employing at least Type SJO or equivalent flexible cords suspended not less than 6 feet (1.83 m) from the floor. (2) Receptacles and attachment plugs installed and used in other-thanhazardous (classified) locations shall be listed for hospital use for services of prescribed voltage, frequency, rating, and number of conductors with provision for connection of the grounding conductor. This requirement shall apply to 2-pole, 3-wire grounding type for single-phase 120-, 208-, or 240-volt, nominal, ac service. (3) Plugs and receptacles rated 250-volt, for connection of 50-ampere, and 60-ampere ac medical equipment for use in other-than-hazardous (classified) locations shall be so arranged that the 60-ampere receptacle will accept either the 50-ampere or the 60-ampere plug. Fifty-ampere receptacles shall be designed so as not to accept the 60-ampere attachment plug. The plugs shall be of the 2-pole, 3-wire design with a third contact connecting to the insulated (green or green with yellow stripe) equipment grounding conductor of the electrical system. 517-62. Grounding. In any anesthetizing area, all metal raceways and metal-sheathed cables, and all noncurrent-carrying conductive portions of fixed electric equipment, shall be grounded. Exception: Equipment operating at not more than 10 volts between conductors shall not be required to be grounded. 517-63. Grounded Power Systems in Anesthetizing Locations. (a) General-Purpose Lighting Circuit. A general-purpose lighting circuit connected to the normal grounded service shall be installed in each operating room. Exception: Where connected to any alternate source permitted in Section 700-12 that is separate from the source serving the emergency system. (b) Branch-Circuit Wiring. Branch circuits supplying only listed, fixed, therapeutic and diagnostic equipment, permanently installed above the hazardous (classified) location and in other-than-hazardous (classified) ARTICLE 517 - HEALTH CARE FACILITIES 70-557 locations, shall be permitted to be supplied from a normal grounded service, single- or three-phase system, provided: (1) Wiring for grounded and isolated circuits does not occupy the same raceway, (2) All conductive surfaces of the equipment are grounded, (3) Equipment (except enclosed X-ray tubes and the leads to the tubes) are located at least 8 feet (2.44 m) above the floor or outside the anesthetizing location, and (4) Switches for the grounded branch circuit are located outside the hazardous (classified) location. Exception: Sections 517-63 (b)(3) and (b)(4) shall not apply in other- I than-hazardous (classified) locations. (c) Fixed Lighting Branch Circuits. Branch circuits supplying only fixed lighting shall be permitted to be supplied by a normal grounded service, provided: (1) Such fixtures are located at least 8 feet (2.44 m) above the floor, (2) All conductive surfaces of fixtures are grounded, (3) Wiring for circuits supplying power to fixtures does not occupy the same raceway for circuits supplying isolated power, and (4) Switches are wall-mounted and located above hazardous (classified) locations. (d) Remote-Control Stations. Wall-mounted remote-control stations for remote-control switches operating at 24 volts or less shall be permitted to be installed in any anesthetizing location. (e) Location of Isolated Power Systems. An isolated power center listed for the purpose and its grounded primary feeder shall be permitted to be located in an anesthetizing location, provided it is installed above a hazardous (classified) location or in an other-than-hazardous (classified) location. (f) Circuits in Anesthetizing Locations. Except as permitted above, each power circuit within, or partially within, a flammable anesthetizing location as referred to in Section 517-60 shall be isolated from any distribution system supplying other-than-anesthetizing locations. 517-64.* Low-Voltage Equipment and Instruments. (a) Equipment Requirements. Low-voltage equipment that is frequently in contact with the bodies of persons or has exposed current-carrying elements shall: (1) Operate on an electrical potential of 10 volts or less, or (2) Be approved as intrinsically safe or double-insulated equipment. (3) Be moisture-resistant. (b) Power Supplies. Power shall be supplied to low-voltage equipment from: (1) An individual portable isolating transformer (autotransformers shall not be used) connected to an isolated power circuit receptacle by means of an appropriate cord and attachment plug, or 70-558 NATIONAL ELECTRICAL CODE (2) A common low-voltage isolating transformer installed in a nonhazardous location, or (3) Individual dry-cell batteries, or (4) Common batteries made up of storage cells located in a nonhazardous location. (c) Isolated Circuits. Isolating-type transformers for supplying lowvoltage circuits shall: (1) Have approved means for insulating the secondary circuit from the primary circuit, and (2) Have the core and case grounded. (d) Controls. Resistance or impedance devices shall be permitted to control low-voltage equipment but shall not be used to limit the maximum available voltage to the equipment. (e) Battery-Powered Appliances. Battery-powered appliances shall not be capable of being charged while in operation unless their charging circuitry incorporates an integral isolating-type transformer. (f) Receptacles or Attachment Plugs. Any receptacle or attachment plug used on low-voltage circuits shall be of a type that does not permit interchangeable connection with circuits of higher voltage. (FPN): Any interruption of the circuit, even circuits as low as 10 volts, either by any switch, or loose or defective connections anywhere in the circuit, may produce a spark sufficient to ignite flammable anesthetic agents. See Section 7-5.1.2.3 of Health Care Facilities, NFPA 99-1990 (ANSI). E. X-Ray Installations Nothing in this part shall be construed as specifying safeguards against the useful beam or stray X-ray radiation. (FPN No. 1): Radiation safety and performance requirements of several classes of X-ray equipment are regulated under Public Law 90-602 and are enforced by the Department of Health and Human Services. (FPN No. 2): In addition, information on radiation protection by the National Council on Radiation Protection and Measurements is published as Reports of the National Council on Radiation Protection and Measurement. These reports are obtainable from NCRP Publications, P.O. Box 30175, Washington, D.C. 20014. 517-71. Connection to Supply Circuit. (a) Fixed and Stationary Equipment. Fixed and stationary X-ray equipment shall be connected to the power supply by means of a wiring method meeting the general requirements of this Code. Exception: Equipment properly supplied by a branch circuit rated at not over 30 amperes shall be permitted to be supplied through a suitable attachment plug and hard-service cable or cord. (b) Portable, Mobile, and Transportable Equipment. Individual branch circuits shall not be required for portable, mobile, and transportable medical X-ray equipment requiring a capacity of not over 60 amperes. (c) Over 600-Volt Supply. Circuits and equipment operated on a supply circuit of over 600 volts shall comply with Article 710. ARTICLE 517 - HEALTH CARE FACILITIES 70-559 517-72. Disconnecting Means. (a) Capacity. A disconnecting means of adequate capacity for at least 50 percent of the input required for the momentary rating or 100 percent of the input required for the long-time rating of the X-ray equipment, whichever is greater, shall be provided in the supply circuit. (b) Location. The disconnecting means shall be operable from a location readily accessible from the X-ray control. (c) Portable Equipment. For equipment connected to a 120-volt branch circuit of 30 amperes or less, a grounding-type attachment plug and receptacle of proper rating shall be permitted to serve as a disconnecting means. 517-73. Rating of Supply Conductors and Overcurrent Protection. (a) Diagnostic Equipment. (1) The ampacity of supply branch-circuit conductors and the current rating of overcurrent protective devices shall not be less than 50 percent of the momentary rating or 100 percent of the long-time rating, whichever is greater. (2) The ampacity of supply feeders and the current rating of overcurrent protective devices supplying two or more branch circuits supplying X-ray units shall not be less than 50 percent of the momentary demand rating of the largest unit plus 25 percent of the momentary demand rating of the next largest unit plus 10 percent of the momentary demand rating of each additional unit. Where simultaneous biplane examinations are undertaken with the X-ray units, the supply conductors and overcurrent protective devices shall be 100 percent of the momentary demand rating of each X-ray unit. (FPN): The minimum conductor size for branch and feeder circuits is also governed by voltage regulation requirements. For a specific installation, the manufacturer usually specifies minimum distribution transformer and conductor sizes, rating of disconnecting means, and overcurrent protection. (b) Therapeutic Equipment. The ampacity of conductors and rating of overcurrent protective devices shall not be less than 100 percent of the current rating of medical X-ray therapy equipment. (FPN): The ampacity of the branch-circuit conductors and the ratings of disconnecting means and overcurrent protection for X-ray equipment are usually designated by the manufacturer for the specific installation. 517-74. Control Circuit Conductors. (a) Number of Conductors in Raceway. The number of control circuit conductors installed in a raceway shall be determined in accordance with