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250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes

Revision

Change Summary

  • Revision to clarify that all equipment grounding conductors associated with any and all circuits in the box must be connected together and to the box and not just each equipment grounding conductors of each associated circuit.
NEC® Text

250.148 Continuity and Attachment of Equipment
Grounding Conductors to Boxes.
Where If circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any all equipment grounding conductor(s) associated with any of those circuit conductors shall be connected within the box or to the box with devices suitable for the use in accordance with 250.8 and 250.148(A) through (E).

Exception: The equipment grounding conductor permitted in 250.146(D) shall not be required to be connected to the other equipment grounding conductors or to the box.

Copyright© 2016 National Fire Protection Association
(See NEC for complete text)

Expert Analysis

Clear directions in 250.148 specify that all of the equipment grounding conductors present in a box or enclosure are required to be connected, regardless of the circuit with which they are associated. The existing exception to 250.148 still applies, giving relief to the equipment grounding conductor of an isolated ground circuit for an isolated ground receptacle not being required to be connected to the other equipment grounding conductors or the box. An equipment bonding jumper is typically required to connect the grounding terminal of a grounding-type receptacle to both a grounded metal box and the supply equipment grounding conductor(s) (EGC). Where one or more EGCs enters a box, they are typically required to be spliced or joined inside the box with suitable devices (listed grounding screws, listed grounding clips, etc.) to bond the box and to connect to the device with a bonding jumper [see 250.146(A) through (D) for exceptions to this general rule].

The removal of a receptacle or other devices or equipment installed in or on the metal box is not permitted to interrupt or break the continuity of the EGC connections to other equipment or devices that are supplied from the same box where EGCs are connected, or to interrupt or break the continuity of the EGC connections downstream. EGCs installed in nonmetallic boxes are required to provide a means of connecting EGCs to receptacles, switches, luminaires, and other equipment installed in or supplied from the nonmetallic box.

A reference to 250.8 was also added to provide guidance on terminating an EGC or bonding jumper to a metal box or enclosure. Section 250.8 is titled, “Connection of Grounding and Bonding Equipment” and gives eight specific list items on permitted methods to properly connect grounding and bonding conductors to metal enclosures.

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