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 [email protected]. Answers are based on the 2014 NEC.


Grounded conductor 
terminations, panelboards


During the bid process for a project in an apartment complex, we ran into several interesting issues. This is a renovation, and all of the existing branch circuits will remain. The engineer’s design shows the panelboards that supply each apartment unit being relocated a distance of approximately 15 feet. The drawing notes require custom covers to be approved, so the original panelboard enclosure can be used as a junction box. The panelboards are feeder-tapped, and the drawings require compliance with 240.21(B)(2). There is a variance in place, and we do not have to comply with 210.12(B) for arc-fault circuit interrupters (AFCIs). The concern we have is that the design shows all existing neutrals and equipment grounding conductors (EGCs) splicing in the old panelboard (junction box) and not terminating in the new panelboard. The engineer has stated (informally) that 408.41 only requires individual termination points for grounded conductors and the installation is permitted. The existing branch circuits will be supplied with conductors in flexible metal conduit. Is that permissible?


Multiple NEC requirements prohibit such an installation. Section 408.41 addresses the termination of grounded conductors in panelboards. It requires each grounded conductor to terminate within the panelboard in an individual terminal that is not also used for another conductor. While some may argue that this rule is directed only at single termination points (not allowing multiple grounded conductors or EGCs under the same screw), the requirement mandates that grounded conductors “terminate within the panelboard.” First-level subdivision 300.3(B) requires all conductors of the same circuit, including the grounded conductor and EGCs, to be installed within the same raceway, etc., unless otherwise permitted in accordance with 300.3(B)(1) through (B)(4). There is permission in 300.3(B)(4) for neutral conductors to terminate/originate in a pull box above a “column-width panelboard” where an auxiliary gutter runs between the panelboard and the pull box. This permissive requirement is limited only to column-width panelboards and does not apply to your installation. Your question did not note the ampacity rating of the feeder or the new feeder tap. It is important to note that the EGC run with the feeder tap must comply with 250.122(G), which requires sizing the EGC according to the rating of the feeder overcurrent protective device but not larger than the tap conductors.


Termination tightening torque


Section 110.14 contains an informational note that recognizes the marked tightening torques on some electrical equipment. Informational notes are not requirements in the NEC. That said, could the electrical inspector check the torque on terminations since it is not a requirement?


The informational note you reference specifically points out that many terminations and equipment are either marked with tightening torque or are identified as with a tightening torque in the installation instructions provided. It is typical for terminations that are listed to be marked with a tightening torque. Section 110.3(B) requires all listed or labeled equipment to be installed and used in accordance with any instructions included in the listing or labeling. Where the equipment is listed or labeled, the electrical inspector can enforce all of the instructions for and markings on listed and labeled equipment. This includes, but is not limited to, tightening torque.


NEC scope


Why is the NEC getting into system design? Every time we get a new Code, more design elements become mandatory. Rules for selective coordination should be left to the designer and not be universally mandated. New rules for circuit breakers in Section 240.87 are another example. Why does the NEC mandate such a rule? We are now required to buy three-pole, 480/277-volt (V) circuit breakers for multiwire branch circuits in commercial venues. I have been installing multiwire branch circuits on single-pole circuit breakers in similar venues for decades. Why change now? This is an installation code, not a design manual. Maybe I am just an old-school guy who is resisting change, but I think these issues are better dealt with in NFPA 70E, not the NEC. Can you provide some reasoning for all of these new requirements?


The purpose of the NEC is contained in “90.1(A) Practical Safeguarding,” as, “the practical safeguarding of persons and property from hazards arising from the use of electricity.” It is imperative to understand that the purpose of the NEC is to “safeguard” persons and property. Note that “persons” is intentionally listed first and includes everyone from families in dwelling units to installer/maintainers­ that may need to work on electrical equipment after initial installation. The purview of the NEC is found in “90.2(A) Covered” as, “the installation of electrical conductors, equipment, and raceways; signaling and communications conductors, equipment, and raceways; and optical fiber cables and raceways.”


Each of the examples you provided in your question is contained in the NEC for the protection of people. Selective coordination is included in multiple sections of the NEC to prevent a cascading outage of systems that are critical to the safety of all people. An example is Section 700.28, which requires overcurrent protective devices (OCPDs) in emergency systems to be selectively coordinated to ensure that, if there is a fault of some type—such as one created by a fire—the loss of power is limited to a single OCPD and not an upstream device that would remove power to unaffected circuits. Section 240.87 requires a means of “arc energy reduction” for circuit breakers rated or set at 1,200 amperes or larger. This requirement is necessary to provide installer/maintainers with the ability to reduce the arc energy when performing justified energized work. The clearing time of the OCPD is directly proportional to the arc energy in a fault.


This requirement also helps protect the equipment and must be in the NEC and not NFPA 70E. Both documents are related to electrical safety, but installation requirements must be in the NEC. Requirements in Section 210.5 for simultaneous means of disconnect of multiwire branch circuits are directly related to safety issues created in an “open neutral” condition and are included in the NEC for the safety of people. It should be noted that you are not required to buy devices that open simultaneously; you can simply use two-wire branch circuits. In 90.1(A), the second sentence clarifies that the NEC is not intended as a design specification or an instruction manual for untrained people. The NEC has included many new requirements over the last few cycles to provide installers and maintainers of electrical systems with the ability to perform their work in a safe manner and to mandate installation requirements where they are necessary for their safety. It is practical to provide means and methods at the time of equipment installation to protect all people, including those that install and maintain electrical systems.


Deicing, snow melting cable, GFCI?


I am going to be installing electrical heating cables in concrete aprons for main access and egress from buildings to melt ice and snow on a college campus over a three-year period as they remove pavers that have suffered due to weather. Is ground-fault circuit interrupter protection (GFCI) required?


No, GFCI protection is not required. However, ground-fault protection of equipment (GFPE) is required for fixed outdoor electric deicing and snow-melting equipment. Article 100 defines a GFCI as a device intended for the protection of personnel that will de-energize a circuit within an established period of time when a current to ground exceeds the values established for a Class A device. The accompanying informational note explains that a Class A GFCI will trip when the current to ground is 6 milliamperes (mA) or higher and will not trip when the current to ground is less than 4 mA. Article 100 also defines GFPE as a system intended to provide protection of equipment from damaging line-to-ground fault currents by operating to cause a disconnecting means to open all ungrounded conductors of the faulted circuit at current levels less than those required to protect the conductors.


The GFPE protection required for snow/ice melting in 426.28 will typically trip in the 30 mA range and is not designed to protect people from shock hazards. All of the requirements in Article 426 also apply. They include, but are not limited to, installation in accordance with manufacturers’ instructions, and visible caution signs or markings to warn others of the presence of the heating cables.