Codes & Standards


Essential to the work of the electrical contractor is knowledge of the National Electrical Code, the National Electrical Installation Standards and additional standards and codes administered by the National Fire Protection Association, the Occupational Safety and Health Administration and others. Here is a list of all our articles on codes and standards listed chronologically by issue date. 

Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Questions can be sent to Answers are based on the 2014 NEC.
 Battery locations

One of the changes in the 2014 edition of the National Electrical Code (NEC) was a new section in Article 110 pertaining to lockable disconnecting means. This is significant because a number of sections throughout the Code contain requirements for disconnecting means.

my april 2015 column, “moving forward,” provided an introduction to a number of public inputs for the 2017 National Electrical Code (NEC). These inputs were submitted to Code-making panel (CMP) 3, and they addressed power over Ethernet (PoE) cables.

Does the National Electrical Code (NEC) require a 480-volt (V), three-phase, 3-wire, delta-connected system to be grounded? No, it is optional. This article examines the NEC’s electrical-system grounding provision.

More on Codes & Standards

Overcurrent Protection, Grounding, Air Conditioning and Refrigerator Equipment, and More

CODE CITATIONS Article 240—Overcurrent Protection Article 250—Grounding Article 430—Motors, Motor Circuits, and Controllers Article 440—Air-Conditioning and Refrigeration Equipment Article 680—Swimming Pools, Fountains, and Similar Installations Overcurrent protection

Group Classifications of Gases or Vapors in a Hazardous (Classified) Location

It is possible to ignite combustible gases or vapors either directly from an arc or spark at the electrical equipment or from the heat generated by the electrical equipment, so extraordinary care must be taken when installing electrical equipment in these areas.

Making Sense of the Tap Rules

Last month we discussedSection 240-21 tap rules, and the effectiveness of the overcurrent protection for the tapped conductors. Sec. 240-21(b)(4) Taps Over 25 ft.

Article 370 - Pull and Junction Boxes

Sizing requirements for boxes and conduit bodies used as pull or junction boxes are stipulated in Section 370-28. While the boxes within the scope of 370-16 are calculated from the sizes and numbers of conductors, boxes in 370-28 are calculated from the sizes and numbers of conduits (raceways).

Overcurrent Protection, Access to Working Space, Snap Switches, and More

CODE CITATIONS Article 110—Requirements for Electrical Installations Article 240—Overcurrent Protection Article 250—Grounding Article 380—Switches Article 384—Switchboards and Panelboards Article 450—Transformers and Transformer Vaults