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. Send questions to firstname.lastname@example.org. Answers are based on the 2017 NEC.
GFCI protection for personnel
While upgrading the fire alarm system on a college campus, their safety guy required us to use plug-in ground-fault circuit interrupters (GFCIs) whenever we were using permanent power for power tools. After we went out and bought a dozen of those, he told us the devices were not portable devices and we could no longer use them. You could put it in your pocket; how is that not portable? We were extremely confused, so we asked him exactly what we should get. He showed us the preferred type of plug-in GFCI, and we bought a dozen of those, which were significantly more expensive. Was he correct? Did we have to buy and use those devices?
Yes, he was correct, and I will explain the NEC requirements to support his position. Section 590.6 “Ground-Fault Protection for Personnel,” applies to temporary power for equipment used by persons during construction, remodeling, maintenance, repair, or demolition or for similar activities. Section 590.6(A)(1) provides specific rules for receptacles that are installed as permanent wiring and requires GFCI protection. This means that for permanent wiring circuits, we can replace a circuit breaker or receptacle with a GFCI device and be compliant. However, that is not practical or feasible. That is the reason that this requirement permits listed cord sets or devices incorporating listed GFCI protection for personnel identified for portable use. This is the key distinction between the GFCI devices mentioned in your question. Both types of devices provide GFCI protection for personnel.
Devices that are “identified for portable use” open both the grounded and ungrounded conductors providing open neutral protection in addition to GFCI protection. This means, if the permanent wiring has a problem, and there is an open neutral conductor, you will not be able to close the device and get voltage on the load side. Devices that are not identified for portable use do not provide open neutral protection, and in the event there is an open neutral on permanent wiring, voltage will exist on the load side of the device and the GFCI will not operate because the brains of the GFCI need 120 volts (V) to work and the neutral is missing. The NEC requires these devices to be identified for portable use.” Some devices provide GFCI protection and are not identified for portable use .
Raceways and Class 2 wiring
We recently had an installation of Class 2 wiring, and where we left the ceiling, we installed conduit. Our apprentice training instructor told us we did not need to follow any of the rules in Chapter 3 of the NEC for raceways or junction boxes when installing a Class 2 wiring system. Is that correct?
In this case, I must disagree with the apprentice instructor. Section 90.3, “Code Arrangement,” very clearly states chapters 1 through 4 apply generally, and that chapters 5, 6 and 7 may supplement or modify the requirements in chapter 1 through 7. Article 725 is permitted to supplement or modify requirements in chapters 1 through 7. Section 725.3, “Other Articles,” states circuits and equipment addressed in this article must comply with articles or sections listed within this section. Additionally, this section states only those sections of “Article 300” referenced in Article 725 apply to Class 1, 2 and 3 circuits. This is the requirement the apprentice instructor was likely referring to when stating the rules for raceways and boxes did not apply.
It is extremely important to understand the section’s first sentence specifically calls out additional requirements that must be followed. The only limiting text in this section is in the second sentence and limits the application of Article 300, not all of Chapter 3. There are 14 first-level subdivisions in 725.3. References within this section to raceways include Section 300.17 for the number and size of conductors in raceway, cable routing systems and communications raceways.
No, we did not forget the cable tray references. Cable trays are not raceways; they are simply used to support and secure. The references to cable routing systems and communications raceways are there to specifically permit those raceways. All the raceways in Chapter 3 are permitted to contain Class 1, 2 and 3 wiring. The requirements for raceways and junction boxes in Chapter 3 apply without regard to what they will contain. Just because those raceways will contain Class 1, 2 or 3 wiring does not mean all other rules do not apply. If we were to buy into that mindset, branch circuits supplying Class 2 power supplies would not be required to follow the requirements of Article 210.
110.26 and low voltage
We have a few scenarios where the applicability of NEC 2017 110.26 “Spaces About Electrical Equipment” is coming into question. Do you think a remote input/output panel, which consists of an enclosure that houses 4-20-milliampere, 24V signal cables and a 24V-powered analog/digital converter, would need to comply with NEC 110.26?
This is the same as a previous bullet item but with the addition of a cord-connected 120V monitoring device within the enclosure.
Section 110.26 specifically addresses low-voltage installations in 110.26(A)(1)(b). This permits smaller working spaces where all exposed live parts operate at not greater than 30V root mean square, 42V peak or 60V DC. It is important to note this permissive requirement mandates special permission, which is a defined term meaning written consent of the authority having jurisdiction. Where the enclosure contains energized conductors and circuit parts at 120V, this permissive requirement cannot be applied, and all of the rules in 110.26 will apply.
Plugging into patient bed location receptacles
We have a sleeper sofa going into a patient bedroom in a hospital. There are four to six hospital-grade outlets hard-wired into the hospital room. The sofa is portable and not hard-wired. (It plugs into the wall to get its connectivity.) The outlet and USB port built into the sofa are for personal use of the patient’s visitors (cellphones, laptops, etc.). The sofa outlet/USB are not intended for medical equipment use; hence, we do not believe this violates Section 517.18(B). Can you please share your expertise based on this scenario?
Section 517.18(B) addresses patient bed location receptacles and not general-use devices. Without a specific exception permitting such use, an authority having jurisdiction would be correct in citing a violation. However, this is likely to be an after-market product installed after the final inspection. I would suggest you attempt to address this in NFPA 99, the Health Care Facilities Code through the public input process.
Readily accessible GFCIs
The new requirement for GFCI receptacles to be readily accessible has created some confusion, in my opinion. One of the local inspectors is enforcing a 5-foot rule. We work primarily in dwelling units and always install a GFCI receptacle in an unfinished portion of the basement to protect UF cable installed underground that terminates into a GFCI-type receptacle. We typically install them above 5 feet high, but they are always easily reached. What is the maximum height to be considered readily accessible in the Code ?
The NEC does not provide a prescriptive height to be considered as readily accessible. As defined, readily accessible means capable of being reached without needing tools, climbing over or under anything, having to remove obstacles or resorting to the use of portable ladders. The inspector is incorrect in mandating a 5-foot rule for being considered as readily accessible. The only prescriptive reference in the NEC for the maximum height of a device is for overcurrent protective devices in 240.24(A). This requirement addresses accessibility, and, in general, mandates that the center of the grip of the operating handle of the switch or circuit breaker when in its highest position cannot be higher than 6 feet, 7 inches above the floor or working platform. If the inspector was referencing 6 feet, 7 inches as the maximum to be considered readily accessible, I would agree.
Cord and cable assemblies from busway
It has always been my understanding that flexible cords and cables cannot be permanently installed. I am presently working in a factory where overhead bus duct supplies equipment with flexible cords and cables that are permanently installed, and in some cases, secured to the building. Is that permitted?
Section 400.12 addresses Uses Not Permitted for the flexible cords and cables referenced in your question. Section 400.12(4) prohibits flexible cords and cables from being attached to building surfaces. However, an exception permits attachment to building surfaces in accordance with 368.56(B). This permits flexible cord and cable as branches from busways to connect portable equipment or stationary equipment to facilitate their interchange. Attachment to the building must be by an approved means, and a suitable take-up tension-support device must be within the first 6 feet of cord/cable.