250.25 Grounding Systems Permitted to Be Connected on the Supply Side of the Disconnect.
Section 230.82 lists several items permitted to be connected to the supply side of an electrical service. These can include but are not limited to:
- Fire pump equipment
- Solar PV systems
- Wind electric systems
- Energy storage systems
- Emergency disconnects
- Meter disconnects
Most of the equipment mentioned above will connect to the service conductors and then terminate in some form of disconnect switch that is suitable for use as service equipment but not technically considered a “service” or a “service disconnect”.
NEC Article 250 has requirements for grounding and bonding of services and separately derived systems, but the items mentioned above do not meet the Article 100 definition of either, and yet they still require bonding and grounding.
Section 250.25 addresses grounding and bonding of supply-side disconnects that are not considered a service. Most of the language just points the code reader to other existing code sections where the requirements can be found.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2020 Code Language:
250.25 Grounding Systems Permitted to Be Connected on the Supply Side of the Disconnect. The grounding of systems connected on the supply side of the service disconnect, as permitted in 230.82, that are in enclosures separate from the service equipment enclosure shall comply with 250.25(A) or (B).
(A) Grounded System. If the utility supply system is grounded, the grounding of systems permitted to be connected on the supply side of the service disconnect and are installed in one or more separate enclosures from the service equipment enclosure shall comply with the requirements of 250.24(A) through (D).
(B) Ungrounded Systems. If the utility supply system is ungrounded, the grounding of systems permitted to be connected on the supply side of the service disconnect and are installed in one or more separate enclosures from the service equipment enclosure shall comply with the requirements of 250.24(E).