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.
During the recent 2017 National Electrical Code (NEC) first revision meetings in Hilton Head, S.C., a number of public inputs were submitted to introduce a new cabling system into Article 725 and Article 760.
My daughter, Trina Bogart, is an emergency department doctor. She recently emailed me a seemingly simple question. However, when I went to the 2014 National Electrical Code (NEC), I realized it was actually more complicated.
The DC Task Group of the NEC Correlating Committee is proposing three new articles for the 2017 edition of the National Electrical Code (NEC). The first is Article 706, covering energy-storage systems (ESS). The second is Article 710, covering microgrids.
I recently taught a 2014 National Electrical Code (NEC) class at an industrial facility in Fort Wayne, Ind., where an attendee asked about special-purpose ground fault circuit interrupters (GFCIs) with trip levels above the normal 4–6 milliampere (mA) trip threshold level.
Some photovoltaic (PV) inverter manufacturers have designed and built transformer-less inverters to add to their existing line of transformer-type inverters for installation in the United States. Transformer-less inverters have been popular in Europe for quite some time.
I recently was asked to review a series of emails from a colleague about equipment requirements for ready access or, as defined in Article 100 and used within text in the National Electrical Code (NEC), as “readily accessible.” This phrase is used to describe the location of circuit breakers, for ex
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.
My last article provided a history and background on Article 400, dealing with flexible cords and cables. This month, I delve further into whether flexible cords and cables could or should be installed in concealed locations.
Concealment of flexible cords and cables that are installed as an integral part of appliances—or when used for connecting other electrical equipment—is an ongoing issue for the electrical industry. The history of the National Electrical Code (NEC) provides some insight.
The concept of modular data centers (MDCs) originated about six or seven years ago as a portable method of delivering information technology data center capacity without the high cost and long construction time.
NFPA 70, the National Electrical Code (NEC), is an installation code, while NFPA 70E is the Standard for Electrical Safety in the Workplace. There is an unofficial line of demarcation between the two documents.
The 2011 National Electrical Code (NEC) introduced changes that required ground-fault circuit interrupter (GFCI) protection to be readily accessible, and the 2014 NEC presents further changes regarding ready access of these devices. Were these changes necessary?
Available fault current, short-circuit current rating, arc energy, arc flash hazards, and incident energy are closely related in both the National Electrical Code (NEC) and NFPA 70E, Standard for Electrical Safety in the Workplace.
For many years, Article 250, which covers grounding and bonding in the National Electrical Code (NEC), only contained two tables. Table 250.122 was used for sizing the equipment grounding conductors, based on the size of the overcurrent protective device in the circuit.
This article returns to the topic of my December 2013 column, which dealt with some of the changes that occurred to 210.12 for arc-fault circuit interrupters (AFCI) in the 2014 National Electrical Code (NEC), such as the expansion of AFCI devices to include circuits for kitchens and laundry equipmen
I made a comment while teaching a class that nonmetallic (NM) cable was not permitted in an outdoor, wet location. An attendee took exception to that statement and asked me to provide National Electrical Code (NEC) justification for the assertion.