More on Chapter 5’s Revisions: Accepting (NEC) change, part 14

By Mark Earley | Mar 15, 2023

There are more updates to Chapter 5 to go through, so let’s continue reviewing those changes.

There are more updates to Chapter 5 to go through, so let’s continue reviewing those changes.

Article 506 Zone 20, 21, and 22 Locations. Several changes were made in Article 506 that are consistent with changes made in Article 500. Changes in Article 500 made it clear that the classification scheme in Article 500 does not include what is covered in Article 506. Article 506 does not cover any of the class/division requirements, nor does it cover Zones 0, 1 or 2.

506.6 Material Groups. The definition of material groups has been updated for consistency with NFPA 499: Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas. Group IIIC consists of combustible metal dusts, including combustible metal fibers/flyings. Group IIIB includes combustible dusts other than combustible metal dust. Group IIIA includes combustible fibers/flyings or ignitible fibers/flyings.

511.2 Other Articles. This new section provides a table of requirements for area classification, equipment and wiring for commercial garages, repair and storage. This table simplifies the use of either the traditional class/division classification system or the zone classification system.

511.7(A) Fixed Wiring Above Hazardous (Classified) Locations. The title has been changed to “Wiring and Equipment Above Hazardous (Classified) Locations.” These spaces are typically not hazardous locations unless lighter-than-air gases are used. Reinforced thermosetting resin conduit (RTRC) was added as a permitted wiring method. If the RTRC is subject to physical damage, Section 355.12(C) would require that it be marked with the suffix “-XW,” which is suitable for areas where it is subject to physical damage. The same change was made in 514.7, for wiring and equipment above hazardous (classified) locations in motor fuel dispensing facilities.

511.8 Underground Wiring Below Hazardous Locations. Article 511 has been revised so it can be used with either the traditional class/division classification or the zone classification system. The title of this section was changed from “Underground Wiring Below Class I Locations” to “Underground Wiring Below Hazardous (Classified) Locations.” This change aligns with the change to 511.2. Changes to allow the use of either classification system were made in 514.4, 514.7, 515.4 and 515.7.

Article 512 Cannabis Oil Equipment and Cannabis Oil Systems. A new Article 512 has been created on cannabis oil equipment and  systems using flammable materials. Flammable materials, including butane, ethanol, hexane, pentane, propane and LPG, are used to extract cannabis oil. Article 512 provides detailed classification diagrams to help evaluate hazardous areas.

516.7(A) Wiring & Equipment Not Within Hazardous Locations. This section was converted into a list format to make it easier to navigate. “Rigid Nonmetallic Conduit” was changed to “PVC Conduit.” RTRC was added as a permitted fixed wiring method. Similar changes were made in 511.7(A) and 514.7(A).

517.6 Patient Care-Related Electrical Equipment. The requirements in the Code for reconditioned equipment have applied to electrical infrastructure equipment. This section was added to exempt patient care-related electrical equipment from the reconditioning requirements. Patient care-related equipment differs from other electrical infrastructure equipment. Healthcare facilities are regulated by a variety of entities, and equipment is subject to requirements for recommissioning or recertification if it is maintained, reconditioned or relocated to ensure it still complies with requirements.

517.10(B) Not Covered. Patient care spaces in healthcare facilities are covered by Part II of Article 517. However, 517.10(B) provides a list of areas that are not covered by Part II. Business offices, waiting rooms, corridors and similar areas in medical, dental and outpatient facilities do not have special wiring requirements because patient care is not provided in those areas. Patient rooms in nursing homes used exclusively for sleeping are also not covered by the wiring requirements of Part II. Words were added to 517.10(B)(2) to make it clear that the governing body of the nursing home determines which rooms are to be used exclusively for patient sleeping.

Two informational notes were also added. The first one points to requirements for tamper-resistant receptacles for certain areas where children may be present. A second informational note was added to point to requirements for AFCI protection in patient sleeping rooms in nursing homes and limited care facilities.

517.13 Equipment Grounding Conductor. Section 517.13 provides the requirements for receptacles and fixed equipment in patient care spaces. Section 517.13(B), Exception No. 2 was moved to become an exception to the main rule of 517.13, which is a more appropriate location for it because it is an exception to the entire requirement, not just for insulated equipment grounding conductors. The exception now permits luminaires located more than 7½ feet above the floor and switches located outside of the patient care area to comply with 517.13(A) or (B), rather than having to comply with both. The requirement in 517.13(B)(1)(3) was rewritten to become a new Exception No. 2, because metal faceplates are grounded to the yoke through the mounting screws rather than through an insulated equipment grounding conductor. Wiring for patient care spaces must comply with 517.13 for the entire run.

517.14 Panelboard Bonding. The terminal buses of the normal and essential branch-circuit panelboards serving the same individual patient-care vicinity are required to be bonded together using a continuous copper conductor not smaller than 10 AWG. If two or more panelboards that serve the same patient vicinity through separate transfer switches are required to be bonded together, they must be bonded through an insulated copper conductor not smaller than 10 AWG. An exception was added to permit the insulated continuous conductor to be terminated on listed connections to aluminum or copper busbars not smaller than ¼ inch thick by 2 inches wide and of sufficient length to accommodate all of the terminations. The busbar is required to be accessible and securely fastened.

517.20(A) Wet Procedure Locations. A new informational note clarifies that “routine housekeeping procedures and incidental spillage of liquids do not define a wet procedure location.” This clarifies that a wet procedure location relates to the medical procedure performed rather than housekeeping to clean the area after the procedure. 

The language in this section was revised to clarify the function of isolated power systems in wet procedure locations. The text previously referred to a power distribution system that inherently limited ground-fault current from the first fault to a low value without interrupting the supply. It was addressing isolated power systems without specifically mentioning them. The changes to this section update this vague extracted language and make it clear that isolated power systems must be used to supply receptacles and fixed equipment in wet procedure locations unless they qualify under the exception.

517.22 Demand Factors. New demand factors have been added for general-use receptacles and individual branch circuits not exceeding 150V to ground. This section points to the demand factors for receptacle loads, which were added to 220.110. 

Header image: shutterstock / IRA_EVVA

About The Author

EARLEY, P.E., is an electrical engineer. Retired from the National Fire Protection Association, he was secretary of the National Electrical Code Committee for 30 years and is president of Alumni Code Consulting Group.





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