Contrasting Two Standards, Rooftop HVAC And More

Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Questions can be sent to Answers are based on the 2017 NEC.

NFPA 70E and the NEC

Both NFPA 70E and the NEC are about electrical safety, so all electricians need both documents. If we combined these documents, we could ensure electrical workers would get both every three years. Most electricians will buy a new Code book but not a copy of NFPA 70E. Why are they separate?

NFPA 70E and the NEC share the common goal of electrical safety. However, they are dynamically different. The NEC deals only with electrical installation requirements, and 70E deals with electrical safety work practices, safety-related maintenance requirements and other administrative controls.

The purpose of the NEC is the “practical safeguarding of persons and property from hazards arising from the use of electricity.” To ensure a safe electrical installation in all occupancies and workplaces, it is imperative to apply a combination of minimum installation requirements (the NEC), qualified installers, competent inspections and applicable product standards.

The purpose of NFPA 70E is to “provide a practical safe working area for employees relative to the hazards arising from the use of electricity.” These requirements apply to employees that will be exposed to an electrical hazard that is not reduced to a safe level by the installation requirements in the NEC. This means employees that may be exposed to energized conductors or circuit parts during the course of their work. NFPA 70E, Standard for Electrical Safety in the Workplace, applies to all workplaces and all employees, not just electricians.

Each of these documents has a significant influence on the other. For example, NFPA 70E requires employees to be provided with ground-fault circuit interruption (GFCI) protection as required by applicable federal, state or local codes and standards. Also, the NEC requires lockable disconnecting means, markings, labels, working space, arc-energy reduction and much more to complement electrical safe work practices. 

Chapters 5, 6 and 7

As a part-time NEC instructor, I was recently asked a question that was difficult to answer regarding the special chapters 5, 6 and 7. All of the articles in Chapter 5, Special Occupancies, are indeed occupancies or areas, except for Article 590, Temporary Installations. Students challenged this, and I agree that temporary power is a special condition and not a special occupancy. Can you explain?

The outline form of the NEC is very carefully designed and works extremely well. Temporary power installations addressed in Article 590 and Section 590.3 apply during construction (includes renovation); for 90 days where holiday lighting, etc., is used; and for emergencies or tests. Indeed, this article does not address a specific occupancy or area but rather a period of time, condition or state of a given occupancy with respect to the lack of permanent power. I suggest you submit a public input to relocate Article 590 into Chapter 7.

EGC for rooftop HVAC

The 2017 NEC now requires raceways supplying HVAC equipment on a roof to include an equipment grounding conductor (EGC). I thought that was already required. Why was this change made?

New Section 440.9 requires “an EGC of the wire type” to be installed in “outdoor portions of metallic raceway systems that use non-threaded fittings.” This applies only to HVAC systems located on a roof where “metallic raceway systems” are used with nonthreaded fittings. This includes EMT, IMC and rigid metal conduit because all are metal and can be used with nonthreaded fittings.

The reason for addressing only metal raceways is Section 250.118 permits these raceways as EGCs. This revision is based on significant substantiation that revealed rooftop wiring methods were subject to ongoing physical damage. This included but was not limited to damage from activities such as snow removal, roof replacement/repair and other maintenance on the roof. 

Where nonthreaded fittings are opened due to physical damage, the ground-fault return path on the metal raceway is lost. Section 440.9 now requires a wire-type EGC to be included to ensure a low-impedance ground-fault path where a nonthreaded fitting may be opened due to physical damage. While this change is safety-driven and intended to ensure EGC continuity, it does not address the physical damage issues. We may see this section revised to prohibit nonthreaded fittings in a future NEC. 

GFCIs for vending machines

During a final electrical inspection of a bank in a retail space, we were asked to show how we provided GFCI protection for two indoor ATMs. We did not provide GFCI protection, because it was not identified on the drawings. To get a final, we had to install two GFCI-type circuit breakers. The inspector claimed the ATMs were “vending machines.” Is that correct?

If the ATM is listed as a “vending machine,” GFCI protection is required. However, I cannot find an ATM that is listed as a vending machine. I have seen a lack of consistent application of NEC requirements for vending machines. 

Prior to the 2017 NEC, Section 422.2 contained a definition that provided significant clarity for Code users. The definition was deleted in the 2017 NEC. The technical committee felt it was no longer needed because a new Section 422.6 requires all appliances operating at 50 volts (V) or more to be listed. The deleted definition clarified that a vending machine was a “self-service device that dispenses products or merchandise without the necessity of replenishing the device between each vending operation and is designed to require insertion of coin, paper currency, token, card, key, or receipt of payment by other means.”

This meant that a vending machine required the insertion of some type of payment and had to dispense a product or some type of merchandise. ATMs identify an authorized customer and dispense currency, not a product. Installers and inspectors no longer have a definition to describe a vending machine and must rely solely on the product marking when it arrives on-site.

Now that the 2017 NEC requires all appliances to be listed, the product standard will determine if a piece of equipment is a vending machine. The scope of UL 751, Standard for Vending Machines, describes vending machines as self-contained, payment-accepting machines that vend products. A product is something that is produced or manufactured and sold to a consumer. The scope of UL 291, Standard for Automated Teller Systems, does not refer to an ATM as a vending machine.

Hospital-grade receptacles

On a recent visit to a new doctor, I noticed the receptacles in the treatment rooms were not hospital-grade. My regular doctor has hospital-grade devices everywhere. Are receptacles in these areas required to be hospital-grade? What is the difference between a hospital-grade receptacle and a standard, general-use device?

In spaces where basic medical care is provided, the NEC does not require ­hospital-grade receptacles, though they are permitted. The general requirements for hospital-grade receptacles are located in sections 517.18 for General Care Spaces (now known as Category 2 Spaces) and 517.19, Critical Care Spaces (now known as Category 1 Spaces). In both Category 1 and 2 spaces, all patient bed location receptacles are required to be “listed hospital grade” and “so identified.” Non-locking-type receptacles in operating rooms must also be “listed hospital grade” and “so identified.”

The identification on the device includes the words “Hospital Grade” or “Hosp. Grade” on the back of the device and a green dot on the face of the receptacle that is visible after installation. See the definition of “patient care space” in 517.2 and the informational notes for more insight. 

A treatment room in a doctors’ office is a basic care space (Category 3). In these spaces, equipment failure is not likely to cause injury to the patients, staff or visitors but can cause patient discomfort. Therefore, hospital-grade devices are not required. In a critical care or general spaces (Categories 1 and 2), equipment failure is likely to cause injury or death to the patients, staff members or visitors, and hospital-grade devices are required.

Hospital-grade receptacles are more robust and are subjected to additional testing not performed on general-use devices, such as grounding, strength, reliability and durability.

Bare EGC

Where more than one type of system is included in the same raceway, the NEC requires all of the conductors to be insulated for the maximum circuit voltage. We installed a 120V circuit in the same conduit with a 277V circuit with the circuit conductors all rated 600V. However, we did use one bare EGC. My partner questioned the use of a bare EGC due to the fact that we had mixed systems. Was this a violation?

No, Section 250.118 permits bare EGCs. The permissive requirement of Section 300.3(C) provides requirements for conductors of different systems. These are current-carrying conductors, including ungrounded and grounded conductors. The requirement is to ensure all current-carrying conductors are insulated at the maximum voltage present and does not apply to the EGC.

About the Author

Jim Dollard

Code Columnist

Jim Dollard is the safety coordinator for IBEW Local 98 in Philadelphia. He is a member of the NEC Correlating Committee, NEC CMP-10, NEC CMP-13, NFPA 70E, NFPA 90A/B and the UL Electrical Council. He can be reached at

Stay Informed Join our Newsletter

Having trouble finding time to sit down with the latest issue of
ELECTRICAL CONTRACTOR? Don't worry, we'll come to you.