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.
 Previous use of gray conductors

Article 310 in the National Electrical Code (NEC) covers general requirements for conductors and their type designations, insulations, markings, mechanical strengths, ampacity ratings and uses.

A recent change in the 2014 National Electrical Code (NEC) creates a new method for determining the size of service and feeder conductors for 120/240-volt (V), single-phase services for one-family, individual units of two-family dwellings, and individual units for multifamily dwellings.

The 2014 National Electrical Code (NEC) has new requirements for field-applied hazard warning markings, signs and labels. Throughout the NEC, rules that required signs, labels and other markings also required a specific signal word be included in the sign, label or marking.

More on Codes & Standards

Is There A Difference?

In the 2005 National Electrical Code (NEC) process, proposals were submitted to change the phrase “equipment grounding conductor” to “equipment bonding conductor” wherever the phrase existed throughout the NEC.

Using Two Cables For A Three-Way Switch, Mixing Plastic And Metal, And More

If you have a problem related to the National Electrical Code (NEC), are experiencing difficulty in understanding a Code requirement, or are wondering why or if such a requirement exists, ask Charlie, and he will let the Code decide. Questions can be sent to

If It Ain't Broke ...

In the March 2012 Electrical Contractor, I mentioned the increased number of receptacles in patient bed locations with a minimum of 14 receptacles in a Category 1 critical-care area and 36 receptacles in a Category 1 operating room for the 2014 National Electrical Code (NEC), based on changes in the

Cords For Temporary Wiring

Recently, the question arose about using cords for temporary wiring. It was interesting to watch the reaction and response. It seems there are considerable inconsistencies relative to this subject.

Sizing Conductors, Part XX

Table 310.15(B)(16) (formerly Table 310.16) in the National Electrical Code (NEC) provides allowable ampacities for insulated conductors rated up to and including 2,000 volts (V).

Protecting Conductors, Undercabinet Lighting and More

Protecting conductors For a 1,200-ampere (A), three-phase, 120/208-volt (V) service, can I run three sets of 500 kcmil underground from the transformer pad to the main 1,200A switch, or does it have to be 600 kcmil?

Sizing Conductors, Part XIX

Article 240 in the National Electrical Code (NEC) provides general requirements for overcurrent protection and overcurrent protective devices. When sizing conductors, the rating of the overcurrent device must be considered.