Code Change Summary: The language on the types of equipment grounding conductors has been revised.

In the past, Section 250.118 provided a list of what is permitted to be used as an equipment grounding conductor. This section has never mentioned what is not permitted to be used as an equipment grounding conductor. That language was located elsewhere in Article 250.

In the 2023 NEC^®, Section 250.118 now has subsection (A) titled “permitted” which contains the existing 14 item list of acceptable equipment grounding conductors, and (B), titled “not permitted” which contains the language previously located in Section 250.121. Grouping what is permitted near what is not permitted makes sense and aligns with similar code structure used throughout the NEC^®.

New Section 250.118(B) prohibits the following from being used as an equipment grounding conductor:

1. Grounding electrode conductors (see exception)
2. The structural metal frame of a building or structure

Equipment grounding conductors are different than grounding electrode conductors.

Equipment grounding conductors serve to provide a ground-fault current path by connecting normally non-current carrying metal parts of electrical equipment to the system grounded conductor or the grounding electrode conductor or both (see Article 100 definition of Grounding Conductor, Equipment).

A grounding electrode conductor connects the system grounded conductor or the equipment to a grounding electrode or to a point on the grounding electrode system (see Article 100 definition of Grounding Electrode Conductor).

An equipment grounding conductor (EGC) is sized differently than a grounding electrode conductor (GEC). EGC’s are sized from Table 250.122 based on the size of the overcurrent device ahead of the circuit. The GEC is sized from Table 250.66 based on the size of the ungrounded service entrance conductors.

Section 250.118(B) prohibits using a GEC as an EGC but there is an exception:

A wire-type EGC installed in compliance with 250.6(A) and the applicable requirements for both the EGC and the GEC in Parts II, III, and VI of Article 250 is permitted to serve as both an EGC and a GEC.

Basically, the exception allows one conductor to serve both purposes as long as it does not carry any objectionable current in accordance with 250.6(A) and meets all of the requirements for both an equipment grounding conductor and a grounding electrode conductor.

Another change in 2023 is the addition of new language in Sections 250.118(A)(5)(f) and (A)(6)(f) regarding flexible metal conduit and liquidtight flexible metal conduit constructed of stainless steel. Stainless steel has a higher resistivity than other metals used in flexible conduits. For these types of conduits, a wire-type equipment grounding conductor or a bonding jumper in accordance with 250.102(E)(2) must be installed to ensure an effective ground fault current path.

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 2023 NEC^® edition of NFPA 70.