Article 110, General Requirements for Electrical Installations: Significant Changes in the 2020 NEC, Part 3

By Michael Johnston | Aug 15, 2019

Part 3 of this series focuses on revisions in Article 110 of the 2020 National Electrical Code (NEC). Article 110 of the NEC, “General Requirements for Electrical Installations,” comprises three parts. Part I contains general requirements, Part II has rules that apply to installations of 1,000 volts (V) nominal or less and Part III provides rules for installations over 1,000V, nominal.

(Editor's Note: To read part 2, click here.)

Section 110.3(B) Installation and Use

Section 110.3(B) was revised and reworded to include the words “or both” in the rule. Equipment that is listed (certified) bears the listing mark, a label or both, often in combination. The revision aligns with the fact that most, but not all, listed equipment is labeled. The new informational note following the defined term “Labeled” provides additional clarification about how certified equipment can be labeled to meet the requirements of applicable product standards.

Section 110.12(C) Cables and Conductors

A new subdivision (C), “Cables and Conductors,” has been added in Section 110.12, “Mechanical Execution of Work.” It includes relocated requirements from the .24 sections from the communications articles in chapters 7 and 8. Conductor and cable support and concerns about damage are addressed in both 110.12(C) and in 800.24.

Section 110.14(D) Terminal Connection Torque

The title of subdivision (D) has been changed from “Installation” to “Terminal Connection Torque.” The term “calibrated” has been deleted from this section because use of a calibrated tool is already implied. Three new informational notes provide practical guidance for installers and inspectors about methods that are used in the field to achieve the required torque values at terminations.

Section 110.21(A)(2) Exception and Informational Notes No. 2 and No. 3

The exception has been revised to provide clarification as to when this exception can be applied. New Informational Note No. 2 explains that terms such as “refurbished,” “rebuilt” or “remanufactured” that are often used interchangeably with the term “reconditioned.” New Informational Note No. 3 explains that the original listing mark could include the mark of the certifying body and not an entire label.

Section 110.22(A) General

A second sentence has been added to Section 110.22(A). Identification of the source circuit supplying the disconnecting means is now required for other than one- and two-family dwelling installations. The revision enhances the ability to readily identify a source disconnect to establish an electrically safe work condition as addressed in NFPA 70E Standard for Electrical Safety in the Workplace.

Section 110.24(A) Field Marking

Section 110.24(A) has been revised for accuracy and clarification. The word “maximum” has been deleted in front of “available fault current” because it is not necessary. New Informational Note No. 2 explains that utilities typically provide and publish available fault current values.

Section 110.26(C)(2) Large Equipment

Section 110.26(C)(2) has been revised and restructured into a list format. Two entrances and egress paths from the work space are required if the sum of the two-to-six service disconnects is (to meet the requirements in 230.71) 1,200 amperes or more. A new last sentence has been added to indicate that open equipment doors on large equipment shall not impede the entry to or egress from the required working space.

Section 110.26(C)(3) Personnel Doors

The words “or listed fire exit hardware” have been added to 110.26(C)(3). An informational note has been added that references two UL standards (UL 305 and UL 10C) that apply to the door hardware this rule refers to. The revision differentiates listed panic hardware from listed fire exit hardware. Note that listed panic hardware could meet the requirements for both standards and be suitable for use as panic hardware in applications where fire exit hardware is also necessary.

Section 110.28 Enclosure Types

Two new informational notes (Nos. 3 and 4) have been added to Section 110.28.

Informational Note No. 3 references the specific “uses permitted” sections with articles 502, 503 and 506. Informational Note No. 4 indicates these types of enclosures are permitted in any unclassified location and limited to Class II, Division 2; Class III, and Zone 22 hazardous (classified) locations.

Section 110.31(A)(4) Locks

Section 110.31(A)(4) has been revised to clarify the personnel door opening must be in the direction of egress. The terms “listed panic hardware” and “listed fire exit hardware” have been incorporated in this section. The informational note to Section 110.26(C)(3) provides references to two UL standards (UL 305 and UL 10C) that address listed panic hardware and listed fire exit hardware.

This series on the 2020 NEC changes continues next month.

About The Author

A man, Mike Johnston, in front of a gray background.

Michael Johnston

NECA Executive Director of Codes and Standards

JOHNSTON is NECA’s executive director of codes and standards. He is a member of the NEC Correlating Committee, NFPA Standards Council, IBEW, UL Electrical Council and NFPA’s Electrical Section. Reach him at [email protected].






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