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. 

For many years, the mystery of area classification has resided with a select group of experts within the electrical, petrochemical and industrial sectors. Many electricians, electrical engineers, fire inspectors and electrical inspectors have remained outside of this group.

In the 2017 National Electrical code (NEC), there are a few changes in 110.26. The first change is in subsection (A), which is part of a global change for the upper voltage threshold.

Before we proceed, in part 3 of this series, the change in Section 230.70(A)(4) dealing with service disconnects on one- and two-family dwellings was reversed during the late stages of the development process and never made it into the 2017 National Electrical Code (NEC).

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 2017 NEC.
 White conductors 
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More on Codes & Standards

Utility-Interactive PV Systems

A utility-interactive photovoltaic (PV) system is defined in Section 690.2 of the National Electrical Code (NEC) (NFPA 70-2005) as a “photovoltaic system that operates in parallel with and may deliver power to an electrical production and distribution network.” NEC Article 690 covers Solar Photovol

When to Supplement

A new definition covering supplementary overcurrent-protective devices has been added to Article 100 in the 2005 National Electrical Code (NEC) to indicate that limited protection may be provided for specific applications or utilization equipment.

Connecting Kitchen Hood Fans, Indoor Receptacles, and More

Laundry GFCI receptacles Q: Are all 15- and 20-ampere, 125V receptacles installed within six feet of a laundry or utility sink in a dwelling occupancy required to be protected by a ground fault circuit interrupter even where the receptacle is not readily accessible such as behind a clothes washer o

Pull and Junction Box Calculations

314.28 Pull and Junction Boxes Article 314 of the National Electrical Code (NEC) covers the installation and use of all boxes and conduit bodies used as outlet, device, junction or pull boxes.

Unplugging Fluorescents

With the acceptance of the 2005 National Electrical Code (NEC), installing and servicing fluorescent luminaires (fixtures) has become a complex situation. The design and layout of the lighting system is critical in determining certain required added features.

Parallel Conductors, Bathroom Circuits and More

Q: Does the National Electrical Code permit Class 2, Class 3 and telephone conductors to be installed in the same bored hole in a wooden stud with Type NM or Type AC cable operating at 120V?

Box-Fill Calculations, Part XII

314.16 Number of Conductors in Outlet, Device, and Junction Boxes, and Conduit Bodies The scope of Article 314 is covered in 314.1 and covers requirements pertaining to the installation and use of all boxes and conduit bodies used as outlet, device, junction or pull boxes, depending on their use, a