Understanding NEC 2023 Sections 230.71, and 225.30
NEC 2023 Sections 230.71(A), 230.71(B), 225.30, and 225.30(B) are often confused because they address similar requirements. However, each section serves a distinct purpose in the design of service disconnects and feeder installations.
This week’s Code of the Week highlights four key NEC sections every electrical engineer, contractor, plan reviewer, and AHJ should understand.
230.71:
Under the 2023 NEC, Section 230.71(A) requires each electrical service to have a single service disconnect. However, up to six service disconnects are permitted when installed in accordance with Section 230.71(B).
230.71(B): Requirements for Two to Six Service Disconnects
Under the 2023 NEC, Section 230.71(B) permits up to six service disconnects for a single electrical service, provided they are installed in compliance with the Code. Depending on the equipment type, the disconnects must be installed in:
⦁ Separate enclosures,
⦁ Separate switchboards,
⦁ Separate switchgear, or
⦁ Separate compartments within a listed metering center.
This section is one of the most significant changes introduced in the 2023 NEC and can directly impact service equipment selection and electrical room layouts.
NEC 225.30: One Supply to a Separate Building
NEC Section 225.30 generally permits a separate building or structure to be supplied by only one feeder or one branch circuit.
Why? A single supply improves safety, simplifies maintenance, and reduces confusion during emergency operations.
Parallel Conductors: Multiple conductors installed in parallel are still considered one feeder, provided they originate from the same overcurrent device and comply with NEC 310.10(G).
Not Permitted: Two or more separate feeders, each protected by its own overcurrent device, supplying the same building, unless permitted by an NEC exception or approved by the AHJ.
NEC 225.30(B)
Under the 2023 NEC, Section 225.30(B) permits up to six feeders to supply a separate building or structure when all feeders originate from the same panelboard, switchboard, or other common distribution equipment and each feeder terminates in a single disconnecting means.
When more than one feeder is installed under this provision:
⦁ All feeder disconnects must be grouped in the same location.
⦁ Each disconnect must be permanently marked to identify the load served.
