Electrical Systems / Electrical Safety

Need to know: New changes to the NEC

The 2017 National Electrical Code features more than 1,000 changes – here are key takeaways.

By Randy Barnett, NTT Training


The National Fire Protection Association (NFPA) issued the 2017 National Electrical Code® (NEC®) last month, and it took effect Aug. 24. “Nice,” you say, “but that is a construction standard and it doesn’t affect our plant operations and maintenance.” Not true! The purpose of the NEC is not to serve as a design or construction manual. The purpose of the NEC is “the practical safeguarding of persons and property from hazards arising from the use of electricity.” That means that nobody gets electrocuted and buildings do not burn down because of an electrical fire.

So, how does this 2017 edition of the Code affect our electrical systems and equipment in our plants and buildings? Here are some examples:

  • A maintenance work order requires the replacement of a receptacle. The receptacle is controlled by the building energy management system and becomes de-energized every workday at 6 p.m., and it’s always off on weekends. According to the 2017 NEC, the replacement receptacle must have the word “controlled” on its face in addition to the international ON/OFF symbol. The receptacles in the warehouse are now out of date for this application and cannot be used. New receptacles to meet the new requirement must be purchased.
  • Some minor electrical work is happening in the break room. A microwave oven is being relocated. The worker knows the new receptacle must be GFCI-protected if it is within 6 feet of the sink. However, does he or she know how the rules have changed for measuring those 6 feet? It could affect the time and materials cost for the work.
  • The additions to this section will provide for the measurement to be the “shortest path” the cord would follow without piercing walls and permanent barriers. So there should be no questions on how to measure around those cabinets. In non-dwelling units, (i.e., the break room), it appears the measurement will now be made from the top inside edge of the sink rather than from the outside edge previously specified. Consider some commercial sinks have large drain-boards attached as well as a backsplash. Determining the edge of the sink could be open to interpretation on some models; this change should eliminate that confusion.
  • If the distance turns out to be greater than 6 feet GFCI, protection is not required. Receptacle cost and possibly installation time will be decreased. On the other hand, if the break room falls under the definition of a kitchen, it will need a GFCI-protected receptacle anyway. While GFCI protection is more expensive, personnel safety can never be compromised. Workers must know the NEC.
  • Installing a motor? You may be able to save some time and money under certain applications by extending the distance that you can run power to that motor.
  • If you run conduits and cables on rooftops, you should know those rules have changed significantly – and engineering and workers will be happy! The Rooftop Adder Table that has affected the ampacity calculations for conductors that are run at a specified distance above a rooftop has been deleted. This table generally hasn’t been well-accepted by electrical personnel since its addition to the NEC several years ago. Because of the deletion, if raceways are kept at least 7/8 of an inch above the rooftop, there should no longer be a need for upsizing conductors and increasing costs.
  • For example, complying with the 2014 NEC required adding 17 degrees C (30 degrees F) to the ambient temperature when performing the conductor ampacity calculation. According to the NEC tables, that reduced the current carrying capacity of a conductor by 25% or more. That meant running larger and more expensive wire or spending money to raise the conduit above the rooftop. With the 2017 NEC, the issue should be alleviated.
  • Getting power to that new skid-mounted air compressor (or other piece of equipment) you just purchased may involve running wires through gutters or wireways. There is a new rule for grouping those conductors. This change was the result of a facility fire! For each circuit, all conductors must be grouped together as they pass through a wireway. (Using a cable tie is probably the quickest and easiest method.) Grouping the conductors means no inductive heating and no overheating of the wireway.
  • Are you installing a new sensor on the wall that turns on the light when people walk into the room? This rule has changed, and it is a little tricky, given that it will not go into effect until 2020. These sensors need to energized at all times for proper operation. Some models have allowed the equipment grounding conductor to be used as a return wire to maintain the circuit. New switches will require a grounded (neutral) conductor be a part of the switch so as not to place this unwanted small amount of current on the equipment ground. To give manufactures time to produce the sensor, the 2017 NEC specifies that this requirement will take effect Jan. 1, 2020.
  • New labeling requirements on motor control centers (MCCs) can help to keep workers safer.
  • There are also new wiring requirements for those HVAC rooftop units (RTUs) as well as for the lights in crawl spaces. Both of these changes were, unfortunately, the result of fatalities.
  • If you have energy storage systems, DC microgrids, certain industrial process heating equipment, large-scale photovoltaic systems, or a stand-alone power system, you should be aware that new individual NEC articles have been devoted to each of those topics. These systems are installed and in use at many facilities, and the new rules in the electrical Code are needed to catch up with these technologies.  

There are more than 1,000 changes to the 2017 National Electrical Code. The previous examples represent just a few topics that plant engineers and workers need to know. Obviously, some of these code changes will apply – some will not. And it’s more than just a compliance issue. Plant managers realize that maintaining compliance is just the tip of the iceberg when it comes to best industry practice. No matter which edition of the NEC is in effect in your jurisdiction, make sure workers are knowledgeable in the latest Code applications that apply to their work. The National Electrical Code changes do affect plant operations and maintenance!