Mark C. Ode

General requirements for conductor connections, terminations, splices and terminal temperatures are covered in 110.14 of the National Electrical Code (NEC). Since 1990, there have been some very substantial changes in 110.14...

I recently received an email from a homeowner who was installing a high-end media room and had questions about his home’s electrical system and the new circuits for the audio/video equipment. Before doing the installation, th...

Transformer installations are common throughout residential, commercial and industrial applications. Most electricians, electrical contractors, electrical engineers and electrical inspectors are familiar with installation req...

Each National Electrical Code (NEC) revision cycle seems to result in a multitude of changes in Article 210, Part III, which covers required lighting and receptacle outlets. There are so many changes in each new Code that ele...

Does the National Electrical Code (NEC) recognize reconditioned electrical equipment, and is such equipment safe? There are many different considerations in this question, and the acceptance of reconditioned electrical equipm...

Two sections in the National Electrical Code (NEC) provide methods of calculating loads for existing installations. One deals exclusively with existing dwelling units, while the other deals with any existing dwellings, commer...

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 elect...

For years, Article 516 of the National Electrical Code (NEC)— covering spray applications, dipping and coating processes using flammable liquids, combustible liquids and combustible powders—did not seem to change much, if at...

Designing and installing specialized electrical equipment with the intent of reducing the incident energy of an arcing fault was first introduced in 240.87 of the 2011 National Electrical Code (NEC) and was further refined in...

Terminology is the vocabulary of technical terms and usages appropriate to a particular trade, science or art. Does it matter what we call something in the National Electrical Code (NEC)? Is there a difference in what somethi...

Those of us who use the National Electrical Code (NEC) on a regular basis and are familiar with the words as well as the intent of the text can often overlook the most obvious interpretations by the rest of the electrical ind...

In the past two National Electrical Code (NEC) cycles, there have been substantial changes in Article 517 dealing with healthcare facilities. While there were some changes in the 2014 NEC, the majority of changes occurred in...