National Electrical Code Articles and Information

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. Health care is what you do to take care of your health. Medical care is what you do after health is compromised. Not34e also that doctors do not graduate from Health School and get an HD. They graduate from medical school and get an MD. Look up any doctor, they have an MD after their name. It was Marcus Welby, MD not Marcus Welby, HD.
   
   The Code-making Panels simply got their English wrong. See the incorrect definition of "health care facilities" in Article 100. 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. And any competent dentist will advise you on dental health: don't drink sodas, don't use mouthwash, don't eat sugary foods, and don't chew on ice cubes. Do floss. 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.
    
2. Grounding is a distinguishing focus of Article 517. You will find references to this time and again, throughout Article 517. However, we run into word misuse again. "Ground" is a connection to the earth (dirt) [Article 100]. It does not create an equipotential plane. For that, you need bonding.
    
3. All branch circuits serving patient care areas must have an effective ground fault path [517.13(A)].
    
4. 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. The principle concept behind "Isolated Ground", aka, IG, is you still bond receptacles to the equipment "grounding" (bonding) conductor but you make the connection as close to the supply as practical. If you draw this out as an electrical circuit and apply basic series-parallel electrical theory, it makes no sense. But it makes people feel better and there are vocal propoents of this arrangement, so it's a required practice. If you are going to use IG keep in mind that you are not actually isolating anything. To do so would invite disaster. See IEEE-142, The Green Book.
    
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. Unlike the situation with IG, this is a very good thing. Refer to the selectivity requirements stated in 517.17(C). Note that 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.
    
7. 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.
    
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. 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. Note the word "systems". It is not unheard of for hospitals to have no backup power when the utility supply goes down, because there's nothing connecting the backup power source to the transfer switch. Even though all the components were tested the system was not. It is much better to schedule a functional test (no surgeries slated for the time slot, etc.) and have a failure that can be addressed with the engineers on site and utility power available to switch back to than to have a failure during an unexpected outage.
    
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. 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].
    
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.