Based on the 2017 NEC

by Mark Lamendola

National Electrical Code Top Ten Tips: Article 517 -- Healthcare Facilities

  1. Article 517 also applies to medical care facilities. In fact, it was originally written and has been subsequently revised with medical care facilities, not health care facilities, in mind.

    The Code-making Panels simply got their English wrong. See the incorrect definition of "health care facilities" in 517.2. Note that this describes medical care facilities, but health care facilities may also come under Article 517.

    Since preventive dental care occurs in a dental office, a dental office is a health care facility that is specifically mentioned in Article 517. As your guide, assume that if the facility has "patients" then it's covered by Article 517.
  2. Grounding is a distinguishing focus of Article 517. You will find references to this time and again, throughout Article 517.
  3. All branch circuits serving patient care areas must have an effective ground fault path [517.13(A)].
  4. A distinguishing aspect of medical care and health care electrical installations is that receptacles have specific grounding requirements. You will find these (and fixed electrical equipment grounding requirements) in 517.13.
  5. You must keep metallic objects bonded, to prevent flashover and other problems. For example, 517.14 requires that you bond the panelboards and related equipment.
  6. Ground fault protection is held to a higher standard than normal, in medical care and health care facilities. Refer to the selectivity requirements stated in 517.17(C).
  7. There are different requirements for general care areas [517.18], critical care areas [517.19], and wet procedure areas [517.20].
  8. The largest Part of Article 517 is Part III: Essential Electrical System. This provides the requirements for a system capable of supplying a limited amount of lighting and power service essential for life safety and orderly cessation of procedures in the event of loss of normal power.
  9. While communications and signaling is normally the purvey of Chapter 8, for medical care and health care facilities there are additional requirements in Article 517, Part VI.
  10. An isolated power system is one comprising an isolating transformer (or equivalent), a line isolation monitor, and its ungrounded circuit conductors [517.2]. The requirements for such systems are in Article 517, Part VII.