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by Mike Holt
Prepare for electrical work in the fast growing healthcare sector.
[ Note: Graphics are not included in the Newsletter ]
Healthcare is one of the fastest growing sectors of the economy. One reason is demographics. As more baby boomers reach retirement age, demand is increasing for new construction, upgrades, and maintenance in healthcare facilities. These facilities include hospitals, outpatient clinics, dialysis centers, cancer treatment centers, dental offices, and long-term care facilities. The growth of the "over 60 club" isn't the only driver. Many lifestyle issues are fueling demand in treatment for problems ranging from adult onset diabetes in teenagers to sports injuries in their great grandparents.
While demand is growing, so are concerns over patient safety, cost containment, regulatory compliance, and litigation. Consequently, Article 517 is now mainstream.
It can seem daunting to learn all 39 definitions in Part I, but it's worth the effort if you are working with healthcare facilities. The requirements in Parts II and III obviously apply to single-function buildings. But, they also apply to individual rooms or areas-such as a doctor's examining room or patient bed location within a multifunction healthcare facility. Where Parts IV through VII apply is evident in their titles.
Part II provides requirements for wiring and protection in patient care areas (defined in 516.2). It does not apply to:
A major goal of Part II is to prevent electrical shock. In healthcare applications, people's bodies are often in direct contact with energized equipment. Thus, Part II provides extensive grounding and bonding requirements-even for something as ordinary as a receptacle.
Patient Care Area Receptacle Rules
You probably consider wiring a receptacle for a residential, commercial, or industrial application one of the simplest jobs an electrician can do. But, wiring a receptacle in a patient care area poses special requirements [517.13] - and it's not simple. The following rules apply to receptacles in such areas.
You must install all branch circuits so they have a ground path for fault current. This means installation in a metal raceway system or a cable armor or sheath assembly-each of which must qualify as an effective ground-fault current path per 250.118. Examples of such a raceway or cable are EMT or Armored Cable (Type AC cable). See Figure 517-1.
The outer metal sheath of interlocked MC cable is not listed as a suitable ground-fault path in 250.118(10); therefore, you cannot use it to supply these branch circuits (Figure 517-4).
AC cable is listed as a suitable ground-fault path because it contains an internal bonding strip of aluminum in direct contact with the outer metal sheath of AC cable [250.118(8)].
If you use FMC for branch circuit wiring, it is limited to the requirements of 250.118(5) and 517.30(C)(3). See Figure 517-3.
Any receptacle supplied by an emergency circuit must not use Type AC, MC, FMC, or any other flexible cable. Emergency circuits must have a nonflexible metal raceway-or MI cable with an additional insulated copper equipment grounding (bonding) conductor [517.30(C)(3)] (some exceptions apply).
You must use an insulated copper equipment grounding (bonding) conductor to ground the grounding terminals of all receptacles (and all noncurrent-carrying conductive surfaces of fixed electric equipment operating at over 100V), if they are likely to become energized and are subject to personal contact.
You must install the equipment grounding (bonding) conductor (sized per Table 250.122) in a metal raceway system or a cable armor or sheath assembly-each of which must qualify as an effective ground-fault current path per 250.118 [517.13(A)]. See Figure 517-2.
These requirements are just for "ordinary" receptacles in patient care areas. What if you are providing power to a room that will use equipment requiring an isolated ground (IG)? Then, things get a bit more complicated.
Per 517.16, the IG receptacle must have the equipment grounding (bonding) conductor required by 250.146(D), and it must be identified by an orange triangle located on the face of the receptacle [406.2(D)]. See Figure 517-6.
But, 517.16 doesn't tell the whole story. The outer sheath of interlocked-type MC cable presents the same problem here as with patient care areas, so you can't use it to supply an IG receptacle-unless the cable contains two equipment grounding (bonding) conductors. You can use interlocked-type AC cable containing a single insulated equipment grounding (bonding) conductor to supply receptacles, because the armor of type AC cable is listed as an equipment grounding (bonding) conductor [250.118(8)]. See Figure 517-7. If you use the AC cable with two insulated equipment grounding conductors, you must use one grounding conductor for the receptacle and one for the outlet box.
While some designers specify IG circuits as an instant fix for power quality problems, the NEC doesn't recommend this as a first line of defense. In fact, the NEC recommends caution (see the FPN to 517.16). An IG does not benefit functionally from any parallel grounding paths, so there are some trade-offs to this solution. The decision to use IG needs to account for the other problems it might create.
Requirements by use
The last three sections of Part II (517.18, 517.19, and 517.20) provide the requirements for specific types of patient care areas-which are defined by their use. These areas are general care, critical care, and wet locations.
General care areas have three requirements:
(A) At least two branch circuits-one from the emergency system and one from the normal system-must supply each patient bed location. All branch circuits from the normal system must originate in the same panelboard (three exceptions apply).
(B) Each "patient bed location" must have a minimum of four hospital grade receptacles. (Figure 517-9).
(C) If you put receptacles in a pediatric ward, use only ones listed as tamper-resistant or ones that employ listed tamper-resistant covers (Figure 517-11).
Critical care areas have six requirements [517.9]. Requirements A, B, and D apply to all receptacles, while requirements C, E, and F are for optional configurations. Critical care requirements are more stringent than general care requirements, as you might expect. For example, 517.19(B) requires each patient area to have at least six receptacles-two more than in general care areas.
Wet locations require GFCIs if interruption of power under fault conditions can be tolerated. If interruption under fault conditions cannot be tolerated, a wet location can be served by an isolated power system.
Essential Electrical Systems for Hospitals
From 517.2, we know an essential electrical system (EES) has the mission of ensuring continuity of electrical power to specific functions and areas of a healthcare facility. Part III provides requirements for meeting that mission, as stated in the scope [517.25].
Hospitals have specific EES requirements [517.13 through 517.35]. Nursing homes also have specific requirements [517.40 through 517.44]. Part III ends with the requirements for other healthcare facilities [517.45]. The requirements for nursing homes and other healthcare facilities refer back to the requirements for hospitals where similar care is provided or life support equipment is required.
One basic requirement for hospitals is the EES must consist of two separate systems, which must be kept entirely separate from all other wiring and equipment. They can't even share raceways, boxes, or cabinets with other wiring. These two systems are:
The wiring of the EES must be mechanically protected, per one of the following wiring methods:
(1) Nonflexible metal raceways, Type MI cable, or Schedule 80 rigid nonmetallic conduit.
(2) Schedule 40 rigid nonmetallic conduit or flexible nonmetallic raceways listed for installation in concrete (where encased in not less than 50 mm (2 in.) of concrete).
(3) Flexible metal raceways and metal sheathed cable assemblies as follows:
(4) Flexible power cords of appliances or other utilization equipment connected to the emergency system.
(5) Secondary circuits of Class 2 or Class 3 communication or signaling systems.
In patient care areas, comply with the requirements of 517.13(A) and (B). For example, do not use nonmetallic raceways for branch circuits that supply patient care areas.
Part IV addresses inhalation anesthetizing locations, and Part V addresses X-Ray installations. Part VII addresses isolated power systems. Part VI addresses specific types of low voltage wiring. To avoid getting a "Code Red" on your healthcare electrical work, make a point of becoming familiar with all seven Parts of Article 517.
If you read the scope of each Part and think of its main goals, you will find the requirements easier to understand and remember. And that can be very healthy for your bottom line.
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