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. 

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.

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.

More on Codes & Standards

Sizing Conductors, Part XXXII

With a lot of work from many dedicated individuals, the 2014 edition of the National Electrical Code (NEC) became available at the end of August 2013. The Code is revised every three years, but the revision cycle has not always been three years. Revision cycles have ranged from one to four years. 

Stay Dry

I made a comment while teaching a class that nonmetallic (NM) cable was not permitted in an outdoor, wet location. An attendee took exception to that statement and asked me to provide National Electrical Code (NEC) justification for the assertion.

Equipment Or Building?

At some properties, a single electric utility service supplies multiple buildings or structures. The service could directly supply one of the buildings, and feeders or branch circuits supply other buildings from that service equipment.

Sizing Conductors, Part XXXI

Tap conductor rules are located in Article 240 in the National Electrical Code (NEC). A tap conductor (as used in Article 240) has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4 [240.2].

AFCIs Settle Into Code

Installation requirements for arc-fault circuit interrupters (AFCI) in 210.12 of National Electrical Code (NEC) have been modified considerably in the past three NEC cycles and have changed dramatically in the 2014 NEC.

Figure 1: 10-foot feeder tap
Applied Tap Rules

Someone recently asked me to explain the differences between the 10-foot tap rule and the 25-foot tap rule as they apply to feeders. An additional question was raised about connecting multiple taps to the same feeder using both the 10- and 25-foot tap rules.

The Best Of Code Question Of The Day, Part III

Charlie Trout, author of Code FAQs and Code Question of the Day, has retired. Enjoy these highlights from his past responses. Sealing conduit that passes into refrigerated room