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. 

The National Electrical Code (NEC) uses the word “harmonic” exactly 11 times, all in combination with or explanation of neutral conductors. However, “harmonic” is not defined in the NEC.

Does the National Electrical Code (NEC) address conductor-withstand ratings for wire-type equipment grounding conductors (EGCs)? Yes, but it is worthy of a more detailed explanation.

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.
 Grounded conductor 
terminations, panelboards

Conductor identification requirements are located in articles throughout the National Electrical Code (NEC). The first such requirement is in Article 110, and it pertains to a specific type of electrical system.

More on Codes & Standards

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

Low-voltage Lighting - Listed Systems or Individual Field-assembled Components?

Does the National Electrical Code (NEC) require all lighting installations operating at 30 volts or less to be Listed systems? Can individual low-voltage lighting components, such as a power supply, fixtures, and conductors be assembled in the field without being part of a Listed system?

How Effective Is Overcurrent Protection in the Tap Rules?

The location in the circuit of the overcurrent protection permitted in the tap rules of Sec. 240-21 raises some questions regarding the effectiveness of the overcurrent protection.