Concluding the 2023 Code Review: Accepting NEC change, part 20

By Mark Earley | Sep 11, 2023
Our Overview of changes in the 2023 National Electrical Code wraps up with a look at the remainder of the updates to Chapter 7, as well as changes to chapters 8 and 9. To read the whole series, visit

Our Overview of changes in the 2023 National Electrical Code wraps up with a look at the remainder of the updates to Chapter 7, as well as changes to chapters 8 and 9. To read the whole series, visit

700.11 Wiring, Class-2-Powered Emergency Lighting Systems. This new section recognizes Class 2 emergency lighting ­systems that could use power over ethernet ­technology or low-power LED luminaires. Some of these Class 2 circuits are also used for ­control functions. Class 2 emergency ­lighting ­circuits must be separated from lighting and power circuits and from other Class 2 circuit ­conductors. If they are ­bundled, they must be bundled separately from other Class 2 nonemergency conductors or cables. If Class 2 emergency circuit conductors are installed alongside nonemergency Class 2 circuits, the Class 2 emergency circuits must be separated by a nonconductive sleeve or a nonconductive barrier. Class 2 emergency circuits require identification to differentiate them from other ­conductors. Section 700.11(D) requires these Class 2 circuit conductors to be protected from physical damage in accordance with 300.4. It also specifies wiring methods. Exceptions to 700.11(D) are permitted for ­certain ­wiring installations that do not exceed 6 feet in length and for certain locked rooms or enclosures. Section 700.27 requires devices that combine control devices with Class 2 emergency power on a single circuit to be listed as emergency lighting control devices.

700.12 General Requirements. Section 700.12(B) was revised to correlate with the occupancy requirements in 700.10(D)(1). ­Section 700.12(C) is now titled ­“Supply ­Duration” to cover the duration of all ­emergency supplies, including fuel sources. Section 700.12(C)(3), Exception, now indicates that an AHJ-approved, public utility-supplied gas system supply for an emergency ­generator does not require an on-site fuel supply. Section 700.12(E) now covers all types of permitted stored energy systems. Section 700.12(G) now covers all microgrid systems. Microgrid systems that supply emergency and nonemergency loads must be ­capable of isolating the emergency loads from the nonemergency loads when there is an interruption of the normal ­supply. Section 700.12(H) now requires battery-equipped emergency luminaires to be listed. 

Similar changes were made in 701.12 for legally required standby systems.

700.24 Directly Controlled Emergency Luminaires. Directly controlled emergency luminaires can be activated in two ways. Some utilize a control signal from an ­external control system that, upon loss of power, activates the luminaire at the required level of illumination. Others are activated by the loss of their control input, which typically results in activation of a relay. Luminaires that operate when activated by an active control signal for a listed external control system are required to be listed. Luminaires that are energized to the required level of illumination by disconnection (loss) of the control input by a listed emergency lighting control device are not required to be listed for use in emergency systems. 

In installations where directly ­controlled luminaires rely on an active control ­signal from a listed external control ­system, both the luminaire and the external ­control ­system must be listed. Luminaires that ­activate upon loss of their control input only require the external emergency control system to be listed. The traditional way of switching ­emergency luminaires is through removal of the control input of a listed ­emergency control device, which is typically a load-­control relay.

700.32 Selective Coordination. Section 700.32 requires selective coordination of overcurrent protective devices (OCPDs) on emergency systems to limit an ­outage as much as possible. Coordination of ­supply-side OCPDs and load-side OCPDs is required to ensure coordination upstream and downstream. 

Sections 700.32(C) and (D) point out that replacement OCPDs and system modifications will affect the coordination, requiring that the selective coordination be reevaluated. 

Similar changes were made in 701.32 for legally required standby systems.

705.5 Parallel Operation. This section was relocated from 705.14, changing the title to the more descriptive “Parallel ­Operation.” Sources operating in parallel must have compatible voltage, wave shape and frequency. 

705.10 Identification of Power Sources. The information on identification of power sources was updated. The directory must provide the location of the disconnecting means. Multiple collocated sources are ­permitted to be identified as a group, rather than needing individual location ­information. This section now requires emergency ­contact information for the off-site service personnel who maintain the installation. 

705.11 Source Connections to a Service. The title makes it clear that it applies to any connection of an interconnected source to a service. The requirements for service ­conductors were moved to 705.11(B). The ­former 705.11(D) was relocated to (C) and was completely rewritten. The new 705.11(E) was added to provide requirements for bonding and grounding. 

705.12 Load-Side Source Connections. A new third sentence indicates that loads for feeders and busbars are based on the ­maximum circuit current calculated in 705.28(A). Where a power control system is installed, the setting of the PCS is the power source output circuit current from the controlled power sources. The previous 705.12(A) was deleted because ­disconnecting requirements are covered in 705.20 and overcurrent protection is covered in 705.30. The requirements that were in 705.12(B) were deleted. The new 705.12(B), Busbars, exempts specifically listed equipment from the requirements of 705.12(B)(3), as those issues are covered by the product listing and instructions. An informational note that follows list item 705.12(B)(6) states that there is specifically designed equipment listed to UL 1741 for combination and distribution of sources to supply loads.

705.20 Source Disconnecting Means. This section covers disconnecting means from other systems on a premises. This ­section specifies seven distinct requirements that must be met. A single disconnect is ­permitted to disconnect multiple sources if it complies with the seven criteria.

705.80 through 705.82 ­Interconnected ­Systems Operating in Island Mode. A new Part III was added to Article 705 to provide requirements for operation in island mode. Systems that operate in island mode must operate with proper voltage and frequency control, or they must disconnect the load.

706.1 Scope. When Article 706 was added to the Code, Article 480 already existed. ­Article 706 was considered to describe a more modern energy storage solution for the newer generation of ­batteries with ­different battery chemistries and high energy ­density. However, there continued to be a need for the standby storage batteries that were traditionally covered in Article 480. For this cycle, the scope of Article 480 was revised to indicate it applies to “installations of ­stationary batteries.” Informational Note No. 2 was revised to point out the differences between Articles 480 and 706. 

706.7 Commissioning and ­Maintenance. Energy storage systems (ESSs) are now required to be commissioned before being placed into service. This does not apply to installations in one- and two-­family ­dwellings. An informational note was added to point to NFPA 855, Standard for the ­Installation of Stationary Energy Storage Systems, for information on commissioning of ESSs. 

706.15 Disconnecting Means. ­Requirements for disconnecting means for ESSs have been expanded. For one- and two-family dwellings, an emergency ­shutdown function must cease export of power from the ESS to the premises wiring of other systems. New requirements were added for disconnecting means for batteries where the battery is separate from the ESS electronics and is subject to field servicing. 

Article 722 Cables for Power-Limited Circuits. Article 722 has been created to cover cable requirements for Class 2 and 3 power-limited circuits, power-limited fire alarm circuits and Class 4 fault-managed power circuits. Many of the installation requirements for these types of cables were previously in Articles 725 and 760. The requirements for Class 4 circuits are new for this cycle.

722.10 Hazardous (Classified) ­Locations. Class 2, Class 3 and Class 4 cables and some fire alarm cables are permitted in ­hazardous (classified) locations where specifically ­permitted in the applicable article elsewhere in the Code. Similar language permitting ­wiring and applicable equipment has also been added to 725.10, 726.10 and 760.10. 

Article 724 Class 1 Power-Limited Circuits. Class 1 power-limited circuit requirements have been moved from ­Article 725 to the new Article 724. These Class 1 circuits are now limited to not more than 30V and 1,000 volt-amperes. The remote control and ­signaling circuits that are not power-­limited are no longer considered to be Class 1 circuits. 

Article 725 Class 2 and 3 Power-Limited Circuits. Requirements for Class 1 circuits have been removed from Article 725, which now only applies to Class 2 and 3 power-­limited remote control and ­signaling circuits. ­General requirements for wiring of Class 2 and 3 circuits have been relocated to new Article 722, including substitution tables, abandoned cables, mechanical execution of work and other requirements that were common to Articles 725, 760 and 770. 

725.31 Safety-Control Equipment. If damage to Class 2 and 3 power-­limited ­safety-control equipment can result in a direct fire or life safety hazard, the ­power-limited circuit must be installed in accordance with 724.31. Class 2 and 3 circuits are no longer permitted to be reclassified as Class 1. However, the circuit would use Class 1 wiring methods. 

Article 726 Class 4 Power Systems. This new article provides requirements for fault-­managed power systems. These ­systems monitor the circuit for faults and control power delivery to ensure that fault energy is limited. These circuits can have a peak ­output voltage of 450V DC line-to-line or 225V DC to ground. 

Article 750 Energy Management Systems. Energy management systems are required to be listed. Three options are provided for listing, including a ­complete listed system, a field installation kit or listed components assembled as a system. Section 750.30(C) was expanded to provide requirements for current set point, system malfunction, ­settings and marking requirements. 

760.24 Mechanical Execution of Work. Fire alarm circuit cables and conductors must be supported by hardware—including straps, hangers and cable ties—that are listed and identified for securement and support. 

Article 800 General Requirements for Communications Systems. During the 2020 cycle, communications circuit requirements were moved from Article 800 to Article 805. A new Article 800, General Requirements for Communications Circuits, was created as a location for the Chapter 8 articles. The task was incomplete in the 2020 cycle. It is now complete. 

Article 810 Antenna Systems. The title of Article 810 was changed from “Radio and Television Equipment” to “Antenna Systems.” 

Chapter 9, Table 13 Equipment ­Suitable for Hazardous (Classified) Locations. A new Table 13, ­Equipment Suitable for Hazardous ­(Classified) Locations, has been ­developed for use in hazardous locations that are ­classified in accordance with either ­classification system.

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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