How are grounding and bonding requirements different in the 2023 NEC for Class II locations?
Overview
Grounding and bonding practices serve as the cornerstone of electrical safety, equipment longevity, fire prevention,
and the overall integrity of the system. These connections must be meticulously established with consideration for the specific location and the type of load they are intended for. NEC Section 502.30 outlines the essential considerations for grounding and bonding in
Class II, Division 1, and 2 locations. In the 2023 edition, this section was updated, leading to the creation of
two distinct subsections (A) and (B). Subsection (A) outlines the provisions for grounding, while subsection (B) covers bonding requirements. This update was introduced to enhance the clarity and facilitate the proper application of grounding and bonding practices.
Applying the 2023 Code
Grounding establishes a connection between a conductive structure and the earth or ground, creating a designated path for fault currents to safely dissipate. This not only mitigates the risk of electric shock to individuals but also serves to safeguard equipment from potential damage. On the other hand, bonding focuses on ensuring that all metal components of electrical equipment and enclosures share the same electrical potential. By doing so, bonding prevents hazardous potential differences that might otherwise result in arcing, sparking, and equipment failure.
NEC Section 502.30 provides instructions for establishing grounding and bonding connections in circuits installed in Class II, Division 1, and Division 2 locations. However, previous editions grouped grounding and bonding provisions under shared subsections, causing confusion in implementation. The 2023 edition addresses this issue by revising the section with clearer language and creating two distinct subsections for grounding and bonding.
What’s New for the 2023 NEC?
The comparison of 2020 NEC and 2023 NEC in terms of Sections 502.30, respectively, is given in the Table below.
2020 NEC |
2023 NEC |
| 502.30 Grounding and Bonding, Class II, Divisions 1 and 2
Regardless of the voltage of the electrical system, wiring and equipment in Class II, Division 1 and 2 locations shall be grounded as specified in Article 250 and in accordance with the requirements of 502.30(A) and (B). (A) Bonding The locknut-bushing and double-locknut types of contact shall not be depended on for bonding purposes, but bonding jumpers with proper fittings or other approved means of bonding shall be used. Such means of bonding shall apply to all intervening raceways, fittings, boxes, enclosures, and so forth, between Class II locations and the point of grounding for service equipment or point of grounding of a separately derived system. Exception: The specific bonding means shall only be required to the nearest point where the grounded circuit conductor and the grounding electrode conductor are connected together on the line side of the building or structure disconnecting means as specified in 250.32(B) if the branch-circuit overcurrent protection is located on the load side of the disconnecting means. (B) Types of Equipment Grounding Conductors Liquidtight flexible metal conduit shall include an equipment bonding jumper of the wire type in compliance with 250.102. Exception: In Class II, Division 2 locations, the bonding jumper shall be permitted to be deleted where all of the following conditions are met: (1) Listed liquidtight flexible metal conduit 1.8 m (6 ft) or less in length, with fittings listed for grounding, is used. (2) Overcurrent protection in the circuit is limited to 10 amperes or less. (3) The load is not a power utilization load.
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502.30 Grounding and Bonding
Regardless of the voltage of the electrical system, wiring systems and equipment shall comply with 502.30(A) and (B). (A) Grounding Wiring systems and equipment shall be grounded in accordance with Part I and Part VI of Article 250, as applicable. (B) Bonding Bonding shall comply with Part I and Part V of Article 250, as applicable, and 502.30(B)(1) and (B)(2). (1) Specific Bonding Means Bonding shall comply with 502.30(B)(1)(a) and (B)(1)(b). (a) The locknut-bushing and double-locknut types of contacts shall not be depended on for bonding purposes, but bonding jumpers with identified fittings or other approved means of bonding shall be used. These bonding means shall apply to all metal raceways, fittings, boxes, cable trays, and enclosures, and other parts of raceway systems between hazardous (classified) locations and the point of grounding for service equipment or point of grounding for a separately derived system. Metal struts, angles, or channels provided for support and mechanical or physical protection as permitted in 335.4(5), 336.10(7)(c), or 722.135(C) shall be bonded in accordance with 250.102. (b) Where the branch-circuit overcurrent protection is located on the load side of the disconnecting means, the specific bonding means shall be permitted to end at the nearest point where the grounded circuit conductor and the grounding electrode conductor are connected together on the line side of the building or structure disconnecting means as specified in 250.32(B). (2) Liquidtight Flexible Metal Conduit Liquidtight flexible metal conduit shall comply with 502.30(B)(2)(a) and (B)(2)(b). (a) Liquidtight flexible metal conduit shall include an equipment bonding jumper of the wire type in accordance with 250.102. (b) In Class II, Division 2 locations, the bonding jumper shall not be required where all of the following conditions are met: (1) Listed liquidtight flexible metal conduit 1.8 m (6 ft) or less in length, with fittings listed for grounding, is used. (2) Overcurrent protection in the circuit is limited to 10 amperes or less. (3) The load is part of a meter, instrument, or relay circuit. |
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