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The 2023 National Electrical Code (NEC) has introduced significant updates and additions to Section 517.30, which governs the sources of power for essential electrical systems (EES) in healthcare facilities. A comparison with the 2020 NEC reveals new provisions and clarified requirements aimed at enhancing safety and reliability in these critical systems.
Two Independent Power Sources (517.30(A))
The 2023 NEC expands the description of the two independent power sources required for EES. Unlike the 2020 NEC, which generically described the normal source supplying the entire electrical system and one or more alternate sources, the updated code specifies that the EES must have two or more independent sources or sets of sources. Both sources must be capable of supplying the entire EES, with at least one source being on-site. The second source is permitted to be either on-site or off-site. Additional sources beyond these two are also allowed but must be sized to supply their intended loads.
An informational note was added in 2023 to clarify that multiple generators combined to serve the EES are an example of a “set of sources.” This addition improves the understanding of configurations that meet the requirements.
Power Sources for the EES (517.30(B))
The 2023 NEC restructured and expanded the types of permissible power sources for EES to include:
The 2023 NEC retains much of the 2020 language but includes clarifications. EES components must still be located to minimize interruptions caused by natural forces or hazards. The requirements for services and feeders remain unchanged but emphasize the importance of physical separation to prevent simultaneous interruptions of the normal and alternate power sources.
Summary of Key Changes and Additions:
The 2023 NEC’s revisions to Section 517.30 demonstrate a continued commitment to safety and adaptability, addressing advances in technology and ensuring robust power solutions for healthcare facilities. These updates provide clearer guidance for designers, inspectors, and facility managers to meet the complex demands of essential electrical systems.
Two Independent Power Sources (517.30(A))
The 2023 NEC expands the description of the two independent power sources required for EES. Unlike the 2020 NEC, which generically described the normal source supplying the entire electrical system and one or more alternate sources, the updated code specifies that the EES must have two or more independent sources or sets of sources. Both sources must be capable of supplying the entire EES, with at least one source being on-site. The second source is permitted to be either on-site or off-site. Additional sources beyond these two are also allowed but must be sized to supply their intended loads.
An informational note was added in 2023 to clarify that multiple generators combined to serve the EES are an example of a “set of sources.” This addition improves the understanding of configurations that meet the requirements.
Power Sources for the EES (517.30(B))
The 2023 NEC restructured and expanded the types of permissible power sources for EES to include:
- Utility Supply Power:
- The 2023 NEC explicitly prohibits the use of utility power as both the normal and alternate source unless permitted elsewhere in the article. This clarification was not present in the 2020 version.
- Informational notes direct users to Sections 517.35 and 517.45 for specific scenarios where dual utility sources are allowed.
- Generating Units:
- This section remains largely consistent with the 2020 NEC.
- Fuel Cell Systems:
- The 2023 NEC incorporates the 2020 requirements but clarifies the installation criteria and continues to require compliance with Parts I through VI of Article 692.
- The updated version retains provisions such as N+1 redundancy, a 10-second load assumption capability, and sufficient fuel supply for essential system types.
- A new requirement in 2023 mandates a connection for a portable diesel generator when life safety and critical portions of the distribution system are present. This addition addresses scenarios where the alternate source might temporarily fail.
- Energy Storage Systems (ESS):
- The 2023 NEC replaces the previous “Battery Systems” with “Energy Storage Systems” to include modern technologies beyond traditional batteries.
- Informational notes reference NFPA 111-2022 for guidance on installing stored electrical energy emergency and standby power systems, updating the reference from NFPA 111-2019.
- Health Care Microgrid:
- This entirely new provision in the 2023 NEC allows healthcare microgrids to serve EES and nonessential loads simultaneously. The microgrid can share distributed resources with the normal system but must be designed to ensure reliability and prevent failure of the EES.
- Informational notes guide users to NFPA 99-2021 for further details on healthcare microgrids.
The 2023 NEC retains much of the 2020 language but includes clarifications. EES components must still be located to minimize interruptions caused by natural forces or hazards. The requirements for services and feeders remain unchanged but emphasize the importance of physical separation to prevent simultaneous interruptions of the normal and alternate power sources.
Summary of Key Changes and Additions:
- Clearer definitions and expanded requirements for independent power sources, specifying on-site and off-site configurations.
- Explicit prohibition of utility power serving as both the normal and alternate source unless otherwise permitted.
- Modernization of alternate source provisions, including the replacement of “Battery Systems” with “Energy Storage Systems.”
- Introduction of health care microgrids as a permissible source for EES.
- Enhanced requirements for fuel cell systems, including a new mandate for portable generator connections in critical applications.
The 2023 NEC’s revisions to Section 517.30 demonstrate a continued commitment to safety and adaptability, addressing advances in technology and ensuring robust power solutions for healthcare facilities. These updates provide clearer guidance for designers, inspectors, and facility managers to meet the complex demands of essential electrical systems.