Before Finishing our review of the changes to Chapter 2 in the 2023 National Electrical Code, I should address some recent changes that came out of the NFPA meeting.
The meeting where the NFPA membership votes on changes to the NEC was held on June 9. The membership adopted 18 amendments to the NEC report, and many are currently being balloted by the Code -making panels (CMPs) and the NEC Correlating Committee. The next two changes came about as a result of the membership meeting.
Article 337. I previously mentioned that the title of Article 337 had changed from “Type P Cable” to “Industrial Mobile Cable, Type IM.” The membership voted to reject the changes to Article 337 that retains the title as it appeared in the 2020 Code . They also voted to globally change all references from “industrial mobile cable” to “Type P cable.” Most of the references to Type P cable are in Chapter 5. The previously mentioned definition of industrial mobile cable in Article 100 will now be the definition for Type P cable.
210.12(B) Dwelling Units. This amendment added a new requirement for providing AFCI protection in dwelling unit bathrooms, with an effective date of Jan. 1, 2025. This will require a ballot of the CMP and the correlating committee.
The change to Article 337 reverts to language in the 2020 NEC, which does not require reconfirmation by the CMP, so it does not get balloted. The change to 210.12(B) is new Code text, which will be balloted by the CMP and Correlating Committee. As I write this column, 210.12(B) is failing ballot. But it isn’t over until it is over. The last stage of the process is an appeal to the NFPA Standards Council. Before this series of columns is complete, I will provide an update on all of the outstanding issues.
Finishing Chapter 2 updates
230.85 Emergency Disconnects. New Section 225.41 has been added for a readily accessible outdoor feeder disconnecting means for dwelling units supplied by feeders. If dwelling unit feeder disconnecting means are provided, a readily accessible outdoor service disconnecting means is not required. If service disconnects are replaced, all of the requirements of this section apply. However, some repairs are permitted.
240.2 Reconditioned Equipment. This is a new section that identifies overcurrent protective devices (OCPDs) that are permitted to be reconditioned and those that are not permitted to be reconditioned. Permitted: Low-voltage power circuit breakers, electromechanical protective relays and current transformers. Not permitted: Equipment providing ground-fault protection, ground-fault circuit interrupters, low-voltage fuseholders and low-voltage nonrenewable fuses, molded-case circuit breakers and low-voltage power circuit breaker electronic trip units.
240.4(B) Overcurrent Devices Rated 800 Amperes or Less. An adjustable-trip OCPD is permitted to be used as long as the setting doesn’t exceed the next standard rating size above the conductor ampacity. The means to adjust the setting of the trip mechanism must have restricted access in accordance with 240.6(C).
240.6(D) Remotely Adjustable Trip Circuit Breakers. These circuit breakers are now recognized and permitted to have an ampere rating equal to the adjusted current setting (long-time pickup setting). Access can be achieved directly through a local non-network interface or through a networked interface where either the circuit breaker and software are identified as being evaluated for cybersecurity or the network has had a documented cybersecurity assessment. Informational notes were added that reference cybersecurity standards on cyberthreats. Another informational note points out the need for continuous vigilance.
240.7 Listing Requirements. New requirements were added to require branch-circuit OCPDs, relays and circuit breakers providing ground-fault protection of equipment and GFCI devices to be listed.
240.11 Selective Coordination. If feeder OCPDs are required to be selectively coordinated with a service OCPD, all feeder OCPDs supplied directly by the service OCPD are required to be selectively coordinated with the service OCPD.
240.24 Location in or on Premises. Several changes were made to this section. The main rule in 240.24(A) requires circuit breakers and switches containing fuses to be readily accessible. The definition of “readily accessible” indicates that if the use of a tool is needed to gain access, it is not readily accessible. The exception to 240.24(A) provided an exception to permit a tool to be used to access industrial control panels and similar enclosures. “Similar enclosures” was deleted because it was vague. The language was revised to permit enclosures designed for hazardous locations and enclosures to protect against environmental conditions. If the enclosure covered by the exception is open, it must comply with 240.24(A).
The general rule of 240.24(B) is that all occupants must have access to OCPDs. Where electric service and maintenance are provided by building management and are under continuous building management supervision, the branch-circuit OCPDs are permitted to be accessible to authorized personnel only. This requirement has applied to guest rooms and suites and now includes sleeping rooms of dormitory units without permanent provisions for cooking.
The prohibition against locating branch-circuit OCPDs in some bathrooms has been expanded to include all bathrooms, showering facilities and locker rooms with showers.
240.89 Replacement Trip Units. Replacement trip units are now required to be listed for use with the circuit breaker type in which it is installed.
A new informational note indicates that the replacement trip unit can be a listed one identical to the original or a different trip unit listed for use with the specific circuit breaker.
242.9 Indicating. There is a new requirement that surge protective devices (SPDs) provide an indication that they are functioning properly.
242.42 Surge Arrester Rating. The duty cycle rating of a surge arrester is now required to be not less than 125% of the maximum continuous system voltage available. For solidly grounded systems, the maximum continuous operating voltage is the phase-to-ground voltage of the system.
The reference to silicon-carbon type surge arresters was deleted because they are no longer manufactured.
245.2 Reconditioned Equipment. Requirements for reconditioned equipment have been updated. Medium- and high-voltage circuit breakers, electromechanical protective relays and current transformers are permitted to be reconditioned. Medium-voltage fuseholders and nonrenewable fuses are not permitted to be reconditioned.
250.6 Objectionable Current. This section requires that the grounding and bonding of electrical systems, circuit conductors, surge arresters, SPDs and conductive, normally noncurrent-carrying metal equipment parts must be installed so they will prevent objectionable current. Section 250.6(B) now provides remedies to objectionable currents resulting from bonding. Section 250.6(C) was revised to recognize that currents may result from abnormal conditions that may not be temporary and could also exist due to required grounding and bonding connections.
250.20 Alternating-Current Systems to Be Grounded. The general requirement of this section is that AC systems are required to be grounded. The words “unless prohibited elsewhere” were added because there are systems where grounding is prohibited. A new informational note provides some examples of specific prohibitions from grounding, and Informational Note No. 2 points to 503.155, 517.61, 517.160, 668.10 and 680.23(A)(2) for examples of circuits that are prohibited to be grounded.
AC systems that are not prohibited or required to be grounded because they are not covered by the conditions in (A), (B) or (C) are permitted to be grounded.
250.24 Grounding of Service-Supplied Alternating-Current Systems. This is one of the sections that was revised to recognize that the term “high-impedance grounded system” is now referred to as “impedance grounded system.” The conductor that connects to the neutral point through an impedance is not a grounded conductor: it is an impedance grounded conductor. Parallel grounded service conductors in two or more parallel raceways are required to be connected in parallel. The size of the grounded conductor in each raceway is to be sized based on the conductors in the raceway.
250.36 Impedance Grounded Systems—480 Volts to 1,000 Volts. This is the main section addressing what are now referred to as impedance grounded systems. Correlating changes have been made in other sections to accommodate this change. The conductor that connects to the neutral point through an impedance is not a grounded conductor: it is an impedance grounded conductor. It is also not a neutral conductor.
250.64 Grounding Electrode Conductor Installation. Copper-clad aluminum conductors are now recognized as suitable for use as grounding electrode conductors. Section 250.64(D)(2)(2) has been revised to recognize that some buildings are supplied by branch circuits rather than feeders or services. A new 250.64(G) was added to prohibit grounding electrode conductors from being run through the equipment’s ventilation openings.
260.68(C) Grounding Electrode Conductor Connections. This section indicates that the interior metal piping that is electrically continuous with a metal underground water pipe electrode that is not more than 5 feet from the point of entrance is permitted to extend the grounding electrode. The measurement of the 5-foot length was clarified in three places to make it obvious that the measurement is along the water piping. In addition, in (C)(2) and (C)(3), there were references to “the usual steel tie wires,“ without explanation. “The usual” was deleted.
250.94(B) Other Means. This section was revised to clarify the requirement for a conductor for the connection to a busbar, which is connected to the grounding electrode conductor. The conductor must be at least as large as the largest conductor connected to the busbar or a 6 AWG copper conductor, whichever is larger.
250.104(C) Structural Metal. This section was revised to replace the vague language about conductors of “sufficient size” with a reference to Table 250.102(C)(1) to specify the size.
Changes were made in 250.104(D)(3) to make it clear that the piping is metal water piping. Changes were also made to recognize that connections to grounding electrodes in the earth may be extended through portions of the pipe or structural electrodes that are above ground provided the installation complies with 250.68(C).
250.118 Types of Equipment Grounding Conductors. This section was reformatted into two subdivisions: (A) Permitted and (B) Not Permitted. A requirement for a bonding jumper was also added to (A)(5)(e) for flexible metal conduit installations where flexibility is needed due to vibration. A similar requirement was added for liquidtight flexible metal conduit in (A)(6)(e). In addition, (A)(5)(f) and (A)(6)(f) were added for locations where there is a need for high resistance to corrosion.
The requirements in 250.118(B), Not Permitted, were previously located in 250.121.
Next month we will begin going over the changes to Chapter 3.