Code Change Summary: Revised code language provides clarity on a power source output connection to a feeder.

In the 2020 NEC^®, the previous language in 705.12(B)(2)(1) has been cleaned up and relocated to 705.12(B)(1) for simplicity.

The revised code language provides two options for making an interconnection between an alternate power source and a feeder. Either option can be used when the connection is made at a location other than the opposite end of the feeder from the primary power source overcurrent protective device (OCPD).

Options (a) and (b) in 705.12(B)(1) specifically apply to the portion of the feeder on the load side of the power source output connection (see image).

When selecting the OCPD for the primary power source feeder, Section 240.4(B) permits the next higher standard OCPD rating (above the ampacity of the conductors being protected) to be used (up to 800 amps). Standard sizes of an OCPD are shown in Table 240.6(A).

Section 240.4(B) cannot be used for the portion of the feeder on the load side of the power source output connection as shown in the image.

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.