Someone recently inquired about the proper wiring methods in a patient care location of a healthcare facility. A few factors relate to this determination. One of the first things is knowing the type of construction for the facility, since the wiring method must be suitable for use where it is installed. Type I construction, for example, is fire-resistive construction, meaning all structural elements and most interior elements must be noncombustible. Interior and nonbearing partitions are permitted to be one- or two-hour-rated construction. Also, Type I construction is permitted for buildings of unlimited height. Informative Annex E of the National Electrical Code (NEC) provides valuable information about the various types of construction from Type I through Type V. This information can be useful in determining suitable wiring methods that can be used in a given occupancy.
In healthcare facilities, some other factors directly affect the type of wiring method, especially if the location is a patient care area. Knowing whether a location is designated as a patient care area or location is significant in making the determination for allowable wiring permitted for those locations. There are specific parts of the Code that can help.
First, healthcare electrical requirements are provided in Article 517 of the NEC, and the various patient care areas are defined in 517.2. The three types of patient care areas defined are general care areas, critical care areas and wet procedure locations. The governing body of the healthcare facility is responsible for designating the patient care areas and the type of care anticipated. The informational note following the definition of patient care area sets a pretty clear demarcation between what constitutes a patient care area and provides examples of areas that do not. This is important in determining the areas where the more specific and restrictive branch-circuit wiring is required.
Part II of Article 517 covers wiring and protection in healthcare facilities, and this is where the requirements for branch circuits are provided. Section 517.10(B) also provides clear language that relaxes the requirements of Part II from certain portions of the healthcare facility, such as waiting rooms, corridors, business offices and so forth. Also in areas of nursing homes and limited care facilities used exclusively for patient sleeping rooms, the more restrictive branch-circuit wiring methods are not required.
All general requirements of chapters 1 through 4 of the NEC apply to wiring in patient care areas. Grounding of receptacles and fixed electrical equipment in patient care areas is more restrictive than what is permitted for general locations. The additional restrictions for wiring in patient care areas are often referred to as redundant grounding wiring in these areas because the Code requires the wiring to be installed in metal raceways or cables that are suitable as equipment grounding conductors in accordance with 250.118, and the system must provide an effective ground-fault current path. The metallic wiring method must also include an insulated copper wire-type equipment grounding conductor sized in accordance with 250.122. The concept is fairly straightforward as are the requirements. The idea is to provide two separate equipment grounding conductor paths; one is the metal wiring method, and the other is the insulated wire. This builds the required redundancy in the grounding and effective ground-fault current path for these circuits. The idea is to install these two separate equipment grounding conductor paths to always be assured in having one. The redundancy ensures effective grounding of noncurrent-carrying conductive parts in the patient care areas and effective overcurrent device operations should a ground fault occur in the branch circuit. An example of an acceptable and common installation is electrical metallic tubing (EMT) installed with 12 AWG insulated copper equipment grounding conductor for a 20-ampere receptacle circuit installed in the examining room of a doctor’s or dentist’s office. A common example of noncompliance is rigid nonmetallic conduit (PVC) installed to a floor box in a dentist’s office and two wire-type insulated equipment grounding conductors. This mistake is made all too often. Although two grounding paths are provided, they are not two separate and different types as required by 517.13(A) and (B).
Many healthcare facility designs typically include a specification that includes this requirement that is consistent with the minimum NEC requirements. It is also a good practice to consult with the local authority having jurisdiction about any other electrical rules that may modify further those minimums in the NEC.