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 email@example.com. Answers are based on the 2017 NEC.
What constitutes livestock?
At a recent Code class, we were told that Article 547 for agricultural buildings applies only where animals are raised for food. Does Article 547 apply on horse and alpaca farms?
Yes. The NEC does not define the term “livestock.” Livestock includes any animal(s) kept or raised for use or pleasure and farm animals kept for use and profit. There is no reference to animals or fish raised for food. See the article scope in Section 547.1(A) and (B). The determination for application of Article 547 is based on excessive litter/feed dust and dust with water or where a corrosive atmosphere exists due to animal excrement or dampness.
Arranged to drain
Are raceways containing fiber optic cables installed on the outside of a building required to be “arranged to drain?” On a recent job, the inspector required us to install a condulet in the middle of a conduit run with a drain fitting installed. I cannot find such a requirement in Article 770 or Article 300?
There are no requirements in the Code for raceways containing fiber optic cable on the exterior of a building with respect to being arranged to drain. However, the NEC contains requirements for raceways on exterior surfaces of buildings or other structures to be arranged to drain. These requirements apply only to outside branch circuits and feeders in Section 225.22 and service entrance conductors in 230.53. Additionally, each of these requirements require the raceways to be listed or approved for use in wet locations.
The NEC revision process for 2020 is underway, and there are public inputs to add this requirement in Article 300. If that revision occurs, this requirement would apply generally for all installations. Fiber optic cables and raceways would not be affected unless the requirement was referenced in Article 770. See Section 770.3.
Common areas included?
Are tamper-resistant receptacles required in hallways and common areas of condominiums and hotels? The Code seems to be unclear on this issue. Corridors in medical, business and dental offices are obviously covered.
Outside of the dwelling unit in condominiums or guest rooms/suites in hotels/motels, tamper-resistant receptacles are not required in hallways, corridors or common areas. Section 406.12 contains requirements for tamper-resistant receptacles. List item (1) includes dwelling units in all areas specified in 210.52 and 550.13. List item (2) includes guest rooms and guest suites of hotels and motels. There is no reference in either of these two list items to hallways, corridors or common areas outside of the dwelling unit, guest room or guest suite. List item (5) prescriptively includes business offices, corridors, waiting rooms and similar areas in clinics, medical and dental offices, and outpatient facilities.
It is common in our area to see pedestal-mounted meter equipment separate from dwelling units. Typically, there are two 200-ampere (A) circuit breakers in the pedestal-mounted equipment. We run PVC underground from the pedestal supplying two panelboards with mains in the dwelling unit. Some inspectors tell us to treat those conductors as service conductors, and others tell us they are feeders. Which is correct?
For the installation you described, the service point—the point of connection between the facilities of the serving utility and the premises wiring—is in the pedestal-mounted meter equipment. Everything downstream of the service point is “premises wiring.” The conductors from the two 200A circuit breakers in the pedestal into the dwelling unit are “outside feeders.” The pedestal-mounted meter equipment is the “service equipment” for this installation.
GFCI for temporary
Changes in the 2017 NEC now require ground-fault circuit-interrupter (GFCI) protection for three-phase receptacles on rooftops and outdoors for devices at 208 volts (V), 100A or less. How does this impact receptacles installed for temporary power? Will the assured equipment grounding conductor program (AEGCP) and special purpose GFCI (SPGFCI) still be permitted?
Yes, the AEGCP and SPGFCI will still be permitted. The requirements in Section 210.8(B) apply generally for all single-phase receptacles rated 150V to ground or less, 50A or less and three-phase receptacles rated 150V to ground or less, 100A or less installed in the locations listed. Section 590.6 contains requirements for GFCI protection of receptacle outlets used in temporary installations. Section 590.6(B) addresses GFCI requirements for all receptacle outlets other than 125V, single phase, 15-, 20- and 30A devices.
There are three methods provided to meet this requirement—GFCI protection in 590.6(B)(1), SPGFCI in 590.6(B)(2) and the AEGCP in 590.6(B)(3). In the first draft stage of the 2017 NEC revision cycle, more requirements were added in Article 100 and 210.8 for SPGFCI devices. However, during the comment stage of the process, those requirements were deleted. It is likely that the permission for SPGFCI in 590.6(B)(2) will be modified in the 2020 revision cycle.
Labels on doors?
Are electrical contractors required to label doors where enclosed equipment is energized at over 1,000V? Are the doors required to be capable of being locked? Is the EC required to put the locking mechanism on the door? This is an ongoing discussion between the engineer, contractor and the construction manager for rooms containing 15-kilovolt (kV) switches supplying primary power in separate buildings.
The general requirement for the marking you reference is found in Section 110.34(C). This requires the entrance to all buildings, vaults, rooms or enclosures containing exposed live parts or exposed conductors operating at more than 1,000V, nominal, to be kept locked unless the entrances are under the observation of a qualified person at all times. It is important to note that this locked door requirement applies only where there are exposed live parts at more than 1,000V.
The EC is not responsible for adding a lock to the door. That is a situation where the authority having jurisdiction must exercise its jurisdiction with the building owner. Section 110.34(C) also contains a second stand-alone paragraph that requires permanent and conspicuous danger signs to be provided. However, this is not tied to the first paragraph, which clearly applies only to exposed live parts or exposed conductors operating at over 1,000V.
I understand your confusion. This subdivision applies to locked rooms or enclosures, but the lock is only required where exposed live parts/conductors exist. No prescriptive guidance is given in 110.34(C) as to where the sign must be applied. The sign is required to comply with Section 110.21(B) and read:
“DANGER—HIGH VOLTAGE—KEEP OUT.”
The 15-kV switches described must also meet the requirements of Article 490 for equipment over 1,000V, nominal. Part III of Article 490 contains requirements for switchgear and industrial control assemblies. The 15-kV switches meet the definition of the term “switchgear” in Article 100. Section 490.35(A) contains requirements for accessibility to energized parts for high voltage (over 1,000V). Doors that can provide unqualified people access to high-voltage energized parts must be locked. The marking requirements are the same as seen in Section 110.34(C). The signs must be permanent and may be installed on the on panels (equipment) or doors (accessing the room) that provide access to live parts.
30 mA for marinas?
New Section 555.3 in the Code requires ground-fault protection (GFP) for all overcurrent protective devices (OCPDs) supplying marinas to not exceed 30 milliamperes (mA). As written, this would include the service, feeder and all branch circuit OCPDs to be ground-fault-protected at 30 mA. How are we supposed to make that work? Ground-fault currents will be cumulative, and upstream devices will open, creating outages and significant problems.
I agree with your assessment. As written, Section 555.3 does not differentiate levels of overcurrent protection. In this case, there is significant benefit in looking at the intent of the technical committee. See first revision 5436, which implemented this 30 mA GFP requirement. The rationale is: “The 30 mA ground fault limit is consistent with that recommended in the Fire Protection Research Foundation report ‘Assessment of Hazardous Voltage/Current in Marinas, Boatyards and Floating Buildings.’”
The conclusion of this report recognizes that some level of feeder protection is required. However, it recognizes that adequate data does not exist with respect to ground-fault conditions in the feeder and recommends a study be performed. It is obvious that the technical committee’s intent was 30 mA ground-fault protection for all shore power within the scope of Article 555. Installers and inspectors cannot modify requirements based on the intent of technical committees; they must comply with NEC requirements as they are written.
At this time, there is a tentative interim amendment (TIA) being balloted by the committee and it is also open for public comment. This TIA proposes elimination of the GFP requirement for the service OCPDs and would require 30 mA ground-fault protection for all feeder and branch-circuit OCPDs. A new last sentence is proposed to permit feeder OCPDs to coordinate with downstream devices to address the problems you raise.