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. Questions can be sent to Answers are based on the 2014 NEC.
 Arc-resistant switchgear

For my December 2005 column in ELECTRICAL CONTRACTOR, I wrote about the installation of parallel conductors in a metal wireway and the subsequent heating effects. These heating effects occur whether the parallel conductors are installed in a metal or nonmetallic wireway or in an auxiliary gutter.

Article 110 in the National Electrical Code (NEC) covers general requirements for the examination and approval, installation and use, access to and spaces about electrical conductors and equipment; enclosures intended for personnel entry; and tunnel installations [110.1].

Special rules for ground-fault protection of equipment (GFPE) apply to healthcare facilities. Section 517.17(A) indicates that these GFPE rules apply to hospitals and other buildings (including multiple occupancy buildings) with critical-care space or where life-support equipment is used.

More on Codes & Standards

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.

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

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].

GFCI protection at in-ground swimming pool

The Best Of Code Question Of The Day, Part II

Charlie Trout, author of Code FAQs and Code Question of the Day, has retired. 
For the rest of 2013, enjoy these snippets from his daily responses.
 Calculating conductors and breakers