250.148 Continuity of Equipment Grounding Conductors and Attachment in Boxes.
Code Change Summary: Revised code language clarifies the continuity of equipment grounding conductors and attachment in boxes.
In the 2020 NEC®, this section was revised for clarity. The section title was changed from Continuity and Attachment of Equipment Grounding Conductors to Boxes to Continuity of Equipment Grounding Conductors and Attachment in Boxes. This small change was needed since not all boxes are metal or provide continuity. Some boxes are plastic and continuity to a plastic box cannot be maintained. In a plastic box, continuity is maintained between the equipment grounding conductors by joining them together inside the box rather than connecting them “to” the box. The remaining subsections were slightly reworded to improve usability.
A proposal was accepted at the first draft meeting but reversed at the second draft meeting that would have required all equipment grounding conductors within a box to be spliced together even if they were just passing through the box without a splice. A public comment made it clear that it was overkill to require every single equipment grounding conductor in an enclosure to be tied together with others from a particular circuit that happen to be spliced inside the box.
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.
2017 Code Language:
250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes. Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any equipment grounding conductor(s) associated with those circuit conductors shall be connected within the box or to the box with devices suitable for the use in accordance with 250.148(A) through (E).
(A) Connections. Connections and splices shall be made in accordance with 110.14(B) except that insulation shall not be required.
(B) Grounding Continuity. The arrangement of grounding connections shall be such that the disconnection or the removal of a receptacle, luminaire, or other device fed from the box does not interfere with or interrupt the grounding continuity.
(C) Metal Boxes. A connection shall be made between the one or more equipment grounding conductors and a metal box by means of a grounding screw that shall be used for no other purpose, equipment listed for grounding, or a listed grounding device.
(D) Nonmetallic Boxes. One or more equipment grounding conductors brought into a nonmetallic outlet box shall be arranged such that a connection can be made to any fitting or device in that box requiring grounding.
2020 Code Language:
250.148 Continuity of Equipment Grounding Conductors and Attachment in Boxes. If circuit conductors are spliced within a box or terminated on equipment within or supported by a box, all wire-type equipment grounding conductor(s) associated with any of those circuit conductors shall be connected within the box or to the box in accordance with 250.8 and 250.148(A) through (D)
(A) Connections and Splices. Connections and splices shall be made in accordance with 110.14(B) except that insulation shall not be required.
(B) Equipment Grounding Conductor Continuity. The arrangement of grounding connections shall be such that the disconnection or the removal of a luminaire, receptacle, or other device fed from the box does not interrupt the electrical continuity of the equipment grounding conductor(s) providing an effective ground-fault current path.
(C) Metal Boxes. A connection used for no other purpose shall be made between the metal box and the equipment grounding conductor(s) in accordance with 250.8.
(D) Nonmetallic Boxes. One or more equipment grounding conductors brought into a nonmetallic outlet box shall be arranged such that a connection can be made to any fitting or device in that box requiring connection to an equipment grounding conductor.