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.
 Grounding electrode
conductor termination

The first National Electrical Code (NEC) was developed in 1897. The National Fire Protection Association (NFPA) became the developer and publisher of the National Electrical Code (NEC) in 1911, and the NFPA continues to develop and publish the Code today.

New text in section 424.66(A) of the 2014 National Electrical Code (NEC) covers working space for electrical enclosures of resistance heating-element-type duct heaters mounted on air-duct systems in limited-access areas.

For many years, The National Electrical Code (NEC) has provided rules for equipment disconnects. NEC requirements are very specific for motors and motor-driven machinery, but they differ from lockout/tagout rules in NFPA 70E, Standard for Electrical Safety in the Workplace. The reason is simple.

More on Codes & Standards

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.

Staying High and Dry

How do you design, protect and locate a dry-type transformer of 600 volts (V) or less so that the installation will comply with the National Electrical Code (NEC)?

Sizing Conductors, Part XVIII

When sizing conductors, more is involved than just selecting a copper or aluminum conductor with the right ampacity from Table 310.15(B)(16) (formerly Table 310.16) in the National Electrical Code (NEC).

Is Switching the Neutral OK?

The other day, A manufacturer inquired about switching the neutral in a branch circuit and whether the 2011 National Electrical Code (NEC) would permit a switched neutral for any application within the Code.

What a Tragedy

A good client summoned me to investigate an accident that occurred when a maintenance electrician was replacing a 30-ampere (A), bolt-in circuit breaker. An electrical arc developed while the electrician was changing out the circuit breaker.

Marking Requirements, Short-Circuit Ratings 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

Rule of Sixes

Lately, I have received questions about the number of disconnects permitted for a building or structure. In one query, an inspection found more than six disconnects were present in an oil and gas refinery building, and it took more than six throws of the hand to disconnect incoming power supplies.