Michael Johnston

If a large quantity of current-carrying conductors is installed in a raceway outside in an ambient temperature that can reach 125°F, what are the Code requirements regarding applied ampacities? These conductors supply...

Common grounding electrodes installed for alternating current outdoor substation grounding are concrete-encased electrodes, ground rings and ground rods. Section 250.191 requires a grounding electrode system in accordance...

May is Electrical Safety Month. As one of OSHA’s “Focus Four,” it is vital that appropriate attention is placed on attaining and maintaining electrical safety in the workplace, not just in May, but year-round. The National...

Article 100 is the keeper of national electrical code definitions. The NEC Style Manual indicates that if a word or term is used in more than two articles, then it should have a definition in Article 100. Article 100 of the...

Communications systems and equipment installed in buildings must comply with the specific rules given in Chapter 8 of the NEC . Even though these systems typically operate at lower energy levels, improper grounding and...

If circuits are intrinsically safe (IS), the energy is at a low enough level that ignition of an explosive atmosphere will not occur if the circuit is opened, shorted or faulted to ground at the same time a fault occurs at...

The National Electrical Code Section 700.10(A) requires all boxes and enclosures­—including transfer switches, generators and power panels that are part of an emergency system—to be marked so they are readily identifiable as...

The National Electrical Code has several requirements applicable to emergency systems, legally required standby systems, essential electrical systems and optional standby systems. From a basic performance standpoint, the...

People are fallible and human error often causes accidents, so assessing worker performance is an important part of maintaining a safe work environment. Incidents can be avoided by understanding what contributes to human...

In 1996, when the National Electrical Contractors Association was developing National Electrical Installation Standards (NEIS) for the electrical construction industry, the initial effort included the development of NECA 1...