NEC Chapter 5 provides requirements for special occupancies and specific rules for electrical equipment installed and operated in hazardous (classified) locations, such as fuel dispensing facilities, chemical plants and bulk...
With so many alternate (standby) power systems being installed in premises wiring systems today, it is appropriate to visit a few National Electrical Code requirements regarding signage for emergency systems, legally required...
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...
The National Electrical Code adoption process is continuously active. Jurisdictions that adopt and use the latest edition of the NEC have the benefits of a Code that has been developed and maintained by qualified technical...
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...
Recently, I was asked to explain the reason for the ferrous metal raceway bonding requirements in 250.64(E). Although the National Electrical Code never uses the term “choke effect,” many in the business understand its...
To understand the purpose of ground-detection equipment installed for ungrounded systems, it is best to have a fundamental understanding of ungrounded system performance and the rules that apply to them. Section 250.4(B)...
Communications systems and equipment installed in buildings must comply with the specific rules provided in Article 770 and Chapter 8 of the National Electrical Code (NEC) . Even though these systems typically operate at...
Installing and operating an ungrounded system is typically a combined effort, including the design or engineering team, the owner, the operators and sometimes the authority having jurisdiction. In addition to the Code...
The NEC Correlating Committee is responsible for the NEC and multiple other electrical codes and standards published by the National Fire Protection Association (NFPA). The committee has a critical obligation to ensure that...
This Article focuses on revisions in Chapter 4 of the 2020 NEC , “Equipment for General Use,” and it includes the requirements for equipment such as switches, luminaires, panelboards, switchboards, transformers, appliances...
Part 4 of this series focuses on revisions in Chapter 2 of the 2020 NEC, “Wiring and Protection.” This article looks at some significant changes in Articles 210, 215, 230, 240 and 250. Section 210.8 GFCI Protection for...
Part 3 of this series focuses on revisions in Article 110 of the 2020 National Electrical Code (NEC). Article 110 of the NEC, “General Requirements for Electrical Installations,” comprises three parts. Part I contains general...
