Electrical Safety Requirements: Patient Care Areas versus Non-Patient-Care Areas
FAQ [Health Devices Mar 1998;27(3):116-7]
Do non-patient care areas have the same electrical safety requirements as patient care areas?
No. Although the hospital is clearly responsible for providing a safe environment for employees, visitors, and
patients, electrical safety requirements in non-patient care areas are not as
stringent as those specified by the National Fire Protection Association (NFPA)
for patient care areas.
In its Standard for Health Care Facilities (NFPA 99),(1) NFPA defines a patient care area as "any portion of a health care facility wherein patients are intended to be examined or treated." For equipment intended to be used within these areas—which include patient, examining, and treatment rooms, as well as any similar areas in which the patient is likely to come into contact with electrical devices—NFPA specifies that chassis leakage currents should not exceed 300 microamperes. (Note that this limit was increased from the pre-1993 limit of 100 microamperes.) However, NFPA does permit exceptions under certain conditions; for example, leakage currents up to 500 microamperes are permitted if the leakage current does not represent a hazard to the patient and if the grounding connection remains intact. Also, when chassis leakage from equipment that will be used in the area exceeds 500 microamperes, NFPA permits the use of leakage current reduction methods, such as adding an isolation transformer or redundant ground.
Within the patient care area, NFPA further requires that any equipment intended for placement near the patient meet additional requirements. NFPA refers to the area near the patient as the patient care vicinity, which it defines as "a space, within a location intended for the examination and treatment of patients, extending 6 ft (1.8 m) beyond the normal location of the bed, chair, . . . or other device that supports the patient . . . [and] vertically to 7 ft 6 in (2.3 m) above the floor." For equipment to be used in this space, NFPA requires that the resistance between conductive chassis surfaces and a reference grounding point not exceed 0.50 W. (NFPA established the concept of a patient care vicinity so that the entire room would not need to meet the stricter requirement.)
In contrast, locations such as business offices, nurses' stations, clinical labs, corridors, waiting rooms, and similar areas are classified as non-patient care areas, and NFPA's electrical safety requirements do not apply. In these areas, ECRI recommends that leakage currents not exceed 500 microamperes. However, because conforming to this limit is not always practical, we consider currents up to 3,500 microamperes to be acceptable where no special risks exist. Although devices with line-cord grounding or double insulation are preferred, devices that are not typically grounded or double-insulated, such as household appliances and office and maintenance equipment, can be used.
- National Fire Protection Association (NFPA). Standard for health
care facilities. Quincy (MA): NFPA; 1996. NFPA 99. Refer to Chapter 7,