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. Send questions to Answers are based on the 2017 NEC.
 Kitchen GFCIs

A friend recently sent me an email with this picture (right) of a manual fire alarm pull station mounted on the side of an electrical panelboard. My friend was inspecting the fire alarm system and was accompanied by the electrician who had installed both the fire alarm and electrical systems.

All of the chapters in the National Electrical Code (NEC) contain tables, but not all of the chapters contain articles. Chapter 9 does not contain any articles; this last chapter only contains tables. The first of two articles in Chapter 1 is Article 100, Definitions.

Reducing differences of potential between conductive equipment or other objects and ground (earth) helps minimize shock hazards in normal circuit operation.

More on Codes & Standards

Residential Calculations

An estimator asked what method to use to calculate the volt-amperes (VA) of a residence. He hoped to use the results as a guide to estimate the elements of the electrical system and wanted the standard method applied.

AFCIs, Coin-Operated Machinery and More

Article 210 Branch Circuits; Article 230 Services; Article 250 Grounding and Bonding; Article 366 Auxiliary Gutters; Article 422 Appliances; Article 517 Health Care Facilities; Various articles in Chapters 6, 7 and 8 are mentioned.

Arcing and Sparking

Many are aware that electrical equipment arcing and sparking -can cause chemical atmospheres (gases, vapors and dusts) to ignite. However, we often forget that thermal ignition of these chemical atmospheres also can occur if the chemicals are exposed to high temperatures.

Diversity Vs. Demand

There are two terms that seem to confuse designers. These terms are “diversity factor” and “demand factor.” To better understand the application of these terms when calculating the load for a service or a feeder supplying a facility, one must understand their meaning.

Current Events

This article is a continuation of designing and installing electrical systems rated over 600 volts. Note that specific equipment as well as wiring methods and other items that form a complete high-voltage system are discussed. Selecting switchgear—490.30 through 490.47