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 codefaqs@gmail.com. Answers are based on the 2014 NEC.

Tape over device terminal screws?

For decades, I have wrapped receptacles and switches with insulating tape before installing the device into a box. I learned to install them in that manner as an apprentice. On a recent job, the foreman told me to not place tape on devices. I know there is a Code rule somewhere that states the exposed screw terminals have to be protected. Can you tell me where the rule is located?

There is no requirement in the NEC or elsewhere that requires any device to be wrapped in tape before installation, but the practice of wrapping devices in tape has been around for a long time. I have been questioned about this practice on many occasions. One justification is that taping devices is necessary because the receptacles/switches will be energized before the finish plates are installed or the tape allows for the removal or replacement of the device while energized. Devices should not be energized before the device cover plates are installed. To do so with standard type screw-terminal devices means there are exposed energized parts creating multiple problems.

The NEC requires cover plates to be installed on completed installations; see sections 110.3(B) and 314.25.

However, the practice of energizing receptacles and switches before the application of cover plates is quite common in construction as a job nears completion. As the temporary power is removed, it is typical to energize newly installed branch circuits for temporary power. In many cases, the permanent cover plates are not yet installed due to wall finishes, such as paint or wallpaper, that are incomplete. Energizing these receptacles is a violation of the NEC as well as Occupational Safety and Health Administration standards. See 29 CFR 1926.416.

Where there is a need to energize permanent branch circuits for temporary power, temporary plastic cover plates should be applied to comply with the NEC and to ensure there are no exposed energized parts. The practice of removing or installing devices while energized would only be recognized as “justified energized work” where de-energizing the circuit would create “additional hazards or increased risk.” See NFPA 70E 130.2(A)(1). Removal while energized would require application of all the safe work practices rules in Chapter 1 of NFPA 70E.

Required grounding electrode?

When we install a service to a building or an outside feeder to a building, we always install a grounding electrode system. At some point, we need clear direction on other locations where a grounding electrode is required. Inspectors in different areas require different grounding electrode installations. For example, we have installed power outlets at recreational vehicle sites without installing ground rods, yet in other jurisdictions, we were required to install two ground rods at each power outlet location. Recently, we had to install ground rods in a parking lot at each electric vehicle charging station. Where are we required to install grounding electrodes? It changes from one area to the next.

The focal point of this issue is the Article 100 definition of the term “structure,” which in the 2014 NEC is defined as, “That which is built or constructed.” This definition is extremely broad in nature and is creating problems. The term is meant to apply to an installation similar in nature to a building. In the Article 100 definition of the term “building,” it is identified as a structure. The problem is that power outlets, electric vehicle charging systems and other electrical equipment that is listed and labeled for use outdoors actually meets the definition of a “structure.” The requirement for a grounding electrode for buildings or “structures” supplied by feeders or branch circuits is in Section 250.32. There is an exception for buildings or structures supplied by a single branch circuit.

All that said, an electrical inspector might look at a piece of electrical equipment that is feeder supplied, identify it as a “structure,” and require a grounding electrode. In my opinion, that was never the intent of Section 250.32.

The good news is that, during the first round of the 2017 NEC revision cycle, the Article 100 definition of “structure” has been modified as, “That which is built or constructed, other than equipment.” By excluding “equipment” in the definition, the grounding electrode requirement in Section 250.32 will no longer apply to power outlets, electric vehicle chargers and other electrical equipment. There are also potential revisions on the way to specifically address this issue in Article 551 for Recreational Vehicle Parks.

Flexible metal conduit as an EGC?

During a recent renovation project that involved a large amount of lighting, I had an issue with the electrical inspection and the reuse of some lighting tails that were installed using flexible metal conduit (FMC). The previous installation was only a few years old, but the spaces changed hands, and new tenants desired a new ceiling and new lighting fixtures. The previous lighting tails were each shorter than 6 feet and protected at 20 amperes (A). The lighting tails did not contain equipment grounding conductors (EGCs) because they met the requirements in 250.118. The electrical inspector asked us for documentation to prove that the existing FMC and fittings were listed. We could not provide such documentation and were forced to install EGCs. Was the inspector correct?

List item (5) in Section 250.118 permits the use of “listed” FMC as an EGC, provided all four of the requirements listed in 250.118(5) are met. The first requirement is that the fittings are also listed. This is obviously where the inspector had an issue. During the initial installation, the installer apparently had access to documentation that both the FMC and fittings were listed. It should be noted that, while 250.118(5) requires “listed” FMC and fittings under prescribed conditions to be used as an EGC, Section 348.6 contains a general requirement that all FMC and associated fittings are to be listed. The problem that inspectors face here is that nonlisted FMC and fittings are readily available. It is for that reason, an inspector should ask to see the coils of FMC and boxes of fittings being used to ensure that they are listed products.

However, in this particular case, the inspector or one of his or her colleagues had approved this job a few years earlier. All of the tails were shorter than 6 feet and protected at not more than 20A as required. Short of listing documentation for the FMC and fittings, the requirements of 250.118(5) were met.

If you were adding FMC tails used as an EGC, it would be your responsibility to prove the products were listed. In my opinion, in this particular case, the inspector should not have required you to install EGCs. While you were unable to provide listing documentation, the same department previously approved the installation, and the inspector did not provide information to prove that the products were not listed.

While discussing the use of FMC as an EGC, it must be understood that 250.118(5) does not permit FMC to be used as an EGC under any circumstances where the FMC is installed because flexibility is required due to vibration or movement. In those situations, an EGC must be installed.

What is a kitchen?

The NEC defines a kitchen as having a permanent means of cooking. If a cord-and-plug microwave is bolted to the wall, do we have a kitchen? Microwaves are used for reheating foods and not for cooking. Shouldn’t the NEC address a range or cooktop to be more prescriptive?

The Article 100 definition of “kitchen” is, “An area with a sink and permanent provisions for food preparation and cooking.” To even consider whether we have a kitchen based on permanent provisions for cooking, a sink along with a permanent countertop or table must be installed for food preparation. Where a range or a cooktop are installed, we obviously have permanent provisions for cooking. Where a receptacle is installed on a countertop and a portable microwave is placed on the countertop, plugged in and used, that is not considered permanent, and, therefore, a kitchen does not exist. Where a microwave, cord-and-plug connected or hardwired, is permanently installed, along with a sink and permanent provisions for food preparation, it is by the NEC definition, a kitchen. I agree with you that, in many cases, such as an office break room, a microwave may be used to simply reheat foods. However, the microwave can be used to cook and is permanently installed, so we have permanent provisions 
for cooking, and thus a kitchen.