National Electrical Code Top Ten Tips: Article 517 -- Healthcare Facilities
- 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. Health care is what you do to take care of your health. Medical care is what you do after health is compromised.
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. In fairness to the CMPs, they are conforming to the word misuse propagated by the medical care and medical insurance industries. Because the misunderstanding is so wide, this approach actually makes their meaning more clear.
Since preventive dental care occurs in a dental office, a dental
office is a health care facility that is specifically mentioned in
Article 517. But a systematic exercise program is core to health care, yet gyms are not covered by Article 517. Similarly, a nutrient-dense diet based on whole foods is core to a health care program, yet the produce department of a grocery store is not covered by Article 517. The difference is a dental office has patients, while a gym has members and a produce department has customers.
As your guide, assume that if the facility has
"patients" then it's covered by Article 517.
- Grounding is a distinguishing focus of Article 517. You will
find references to this time and again, throughout Article 517.
- All branch circuits serving patient care areas must have an
effective ground fault path [517.13(A)].
- A distinguishing aspect of Article 517 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.
- 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.
- 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). Note tha the feeder device, not the service device, must open if there's a ground fault on the load side of the feeder device. This requirement follows the same logic as selectivity for circuit breakers. You want the circuit interruption as close to the problem source as possible. It's better to open a feeder for a problem on that feeder than to open the service. You should extend this concept to branch circuits, as well.
- There are different requirements for general care areas
[517.18], critical care areas [517.19], and wet procedure areas
[517.20]. Note that general care areas are also designated Category 2 and critical care areas are designated Category 1. But wet procedure locations don't have a Category designation.
- 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. Note that when we say "provides the requirements" we mean the minimum for electrical safety per 90.1. The requirements for meeting performance and reliability goals are in other standards. Also, deep expertise is needed for things such as proper testing and commissioning of UPS systems.
- 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. This is a very short section. It provides a short requirement for patient care spaces, basically saying this equipment must meet the insulation and isolation requirements for patient care spaces [517.80]. It also provides a short requirement for other spaces, saying they "must comply with other parts of this Code" [517.81].
- 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.