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. 

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 
in cable assemblies

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.

More on Codes & Standards

Overcurrent Protection, Disconnecting Means and Mo

Disconnecting means Q: Disconnecting means for circuits supplied by a generator are required where the circuits enter a building or structure. Are these disconnects from an outdoor generator required to meet the rules in Article 225? Is there a maximum number of disconnects permitted?

Branch-Circuit, Feeder and Service Calculations, Part III

220.14 Other Loads—All Occupancies Article 220 of the National Electrical Code (NEC) contains requirements for calculating branch-circuit, feeder and service loads. Knowing how to perform load calculations is an essential part of being an electrician.

A Concept Change

Hidden within the rewrite of Articles 511 and 514—which cover repair garages for motor vehicles and motor fuel dispensing stations, respectively, in the 2005 National Electrical Code (NEC)—is a major change in the concept of hazardous (classified) locations.

Entries into Raintight Enclosures, Derating NM-B C

Cables in metal framing member Q: Sections 320.17 and 330.17 require that Types AC and MC cables be installed to comply with 300.4.

Branch-Circuit, Feeder and Service Calculations, Part II

An essential part in the life of an electrician is performing load calculations. Determining what size conductors and overcurrent protective devices to install is something most electricians do on a daily basis.

Household Applications and the Code

Providing branch-circuit overcurrent protection and subdividing electrical resistance-heating elements in appliances and fixed electric space heating equipment has been a long- standing requirement in the National Electrical Code (NEC).

Mission Critical

A new article has been proposed for the 2008 National Electrical Code (NEC) covering mission-critical electrical systems installed in vital infrastructures or facilities where, if the infrastructure or facility was either destroyed or incapacitated, disruption of the facility would affect national