Published In September 2001
As the Baby Boomers of our society reach their golden years, the need for more and more nursing home facilities will become imperative. Electrical contractors will be faced with the responsibility of properly installing many different sophisticated systems within these nursing homes. Telephones, TV, broadband, and other forms of telecommunications systems must be installed in these buildings in accordance with the requirements in Chapter 8 of the National Electrical Code (NEC), while still maintaining the safety mandated by Article 517 for health care facilities. The definition of a nursing home, located in Section 517-3 of the NEC, states that it can be a separate building or a portion of another building. A nursing home is used for lodging, boarding, and nursing care on a 24-hour basis of four or more people who may or may not be capable of providing for their own needs and safety without another person’s assistance. Based upon this definition, different levels of nursing care are provided at these facilities. There are apartment or assisted-living facilities that provide very minimal maintained care and have nursing staff available for emergency purposes only. There are also convalescent homes that provide a moderate level of nursing care. The final three types of facilities are skilled nursing, intermediate care, and infirmaries for the aged with mental and/or physical incapacity. These last three facilities require the most electrically sophisticated equipment and wiring systems to protect the patients from possible sources of electrical current. Patients may be connected to electrical equipment while being exposed to other equipment in the general area. The two electrical systems must be compatible with each other, while not exposing the patient to possibly hazardous currents that may flow between the two different systems. For the simple assisted living facilities, Cable TV and telephone wiring is very straightforward. Section 517-10(b)(2) permits areas of nursing homes and limited care facilities used exclusively as patient sleeping areas to be wired in accordance with the requirements in Chapters 1 through 4 of the Code. It does not require redundant grounding of fixed electrical equipment and receptacles, special panelboard grounding and bonding, or special hospital-grade receptacles. Since these sleeping areas are not considered to be patient care areas, Section 517-81 requires installation of any communications, signaling, data, fire alarm, or any system of less than 50 volts to comply with the appropriate article covering that type of system. However, as the nursing home deals with critical care of their patients, more sophisticated electrical equipment is required in conjunction with the patients. It becomes imperative to ensure that the patient care area does not have electrical equipment that may develop a difference of voltage between any two different pieces of electrical equipment. Section 517-80 requires equivalent insulation for low-voltage electrical equipment as is used in higher-voltage equipment. Care must be taken to ensure similar electrical isolation for the lower-voltage systems as taken for the higher-voltage systems. Any leakage between electrical equipment and ground or to another piece of electrical equipment could endanger the patient. Patient care areas within nursing home facilities where the patient may be connected to monitoring devices and other electrical equipment, must comply with the requirements for redundant grounding in accordance with Part B of Article 517. Low-voltage systems must also comply with Section 517-82 to ensure that low-voltage system cabling and any grounding wires connected to an electrical appliance in the vicinity of the patient employ a signal transmission system that prevents hazardous potentials between appliances. One method of ensuring that all of the electrical appliances in the patient vicinity are at the same grounding potential is to provide a grounding connection between all equipment in the patient care area. This is commonly accomplished by using a ground reference point where all electrical equipment is grounded back to a common point. In the case of a cable TV system using coaxial cable, the coaxial cable shield could be grounded where it enters the building, as required by Section 820-33, but the shield is left ungrounded at the equipment end. Leaving the cable shield ungrounded at the equipment end maintains the shielding for the TV transmission signal. The TV equipment would then be connected to the patient ground reference point established within the patient vicinity. With both the low- and high-voltage electrical equipment grounding connected to the ground-reference connection, the patient would not be exposed to any noncurrent-carrying metal equipment that was not at other than a zero-potential difference. Other than these special precautions to ensure no difference of potential between equipment, the coaxial cable TV systems would be subject to all of the same requirements as covered in Article 820 for any cable TV system. Section 820-53 requires plenum cable where the coax is installed in a duct, plenum, or other space used for environmental air. This section also requires a riser cable where the cable is installed in a vertical run and penetrates more than one floor. If the cable is not installed in a plenum or vertical run from floor to floor, general-use CATV cable can be used for the general wiring of the system within the building. ODE is staff engineering associate at Underwriters Laboratories, Inc., in Research Triangle Park, N.C. He can be reached at (919) 549-1726 or via e-mail at firstname.lastname@example.org.