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...
My Inspiration for this column came from a discussion on a Facebook nostalgia group. The question was “Who remembers the Great Northeast Blackout [of 1965]?” I scanned the various posts about where people were and how they...
One of the protection techniques recognized in 500.7(K) in Article 500, covering general protection installations in a hazardous location, is the use of a combustible-gas-detection system. In the years since the 2002 National...
Jim Dollard has an extensive background in codes and standards. Send questions about the National Electrical Code (NEC) to Jim at codefaqs@gmail.com. Answers are based on the 2020 NEC. Is an Airbnb space a guest room? The...
In my July column, I reviewed the reason and importance for performing battery calculations. In this article, I will continue the conversation and review voltage-drop calculations. There has been some confusion about what...
These briefings are intended to help contractors hold safety meetings on the job site. Temporary wiring for construction activities involves many phases of work: Determine which codes apply. Determine the power requirements...
Jim Dollard has an extensive background in codes and standards. Send questions about the National Electrical Code (NEC) to Jim at codefaqs@gmail.com. Answers are based on the 2020 NEC. Switchboard in a flood A fitting on a...
I recently had new air conditioner units and a new swimming pool circulation motor installed at my home. The installer asked if I wanted soft or hard start units installed on these motors for a nominal fee. Not knowing that I...
For the National Electrical Code to be a complete regulation for the built environment, it must contain sufficient requirements to cover the overwhelming number of possible installations. Where it does not specifically...
In the past three editions of the National Electrical Code (2014, 2017 and 2020), we have seen major changes in the requirements for electrical systems in healthcare facilities. In the 2014 NEC, the reference to requirements...
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...
I received an email recently from a good friend requesting I write an article on knob-and-tube wiring. This request brought back memories of when I was an electrical contractor in the Phoenix area, licensed for 600V and lower...
Jim Dollard has an extensive background in codes and standards. Send questions about the National Electrical Code (NEC) to Jim at codefaqs@gmail.com. Answers are based on the 2020 NEC. GFCIs in elevator pits During an...
The year 2020 was unique. Most of us had to find a different way to do our jobs to stay in the game. This was also true of the National Electrical Code. A process that relies on the interpersonal actions of technical...
Section 90.2(B)(5) states that the National Electrical Code does not apply to installations that are under the exclusive control of the electric utility company. Has anyone ever questioned the validity of this requirement...
Widespread power outages, power failures in commercial and industrial facilities, construction in areas where electric service is unavailable, debris cleanup and essential service restoration following storms or human-caused...
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...
When a homeowner ASKs an electrical contractor to add extra circuits and receptacles to an existing home, does the 2020 National Electrical Code permit them to be added to bathrooms, kitchens and garages? Adding new circuits...
Certain phrases are used so commonly in the electrical industry that an explanation seems to be almost unnecessary. However, the definition might not specifically be found within the National Electrical Code. One phrase that...
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...
