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 2017 NEC.
White conductors in cable assemblies
When using Type MC or other cable assemblies for lighting in a commercial occupancy, we are required to identify the white or gray conductor used as a switch leg as a hot conductor. This means we have to stop and place tape on the white or gray conductor at each switch location. Why is this a requirement? All electricians understand how switch legs function.
The general rule in Section 200.7(A) requires conductors with white or gray insulation to be used only for the grounded circuit conductor unless otherwise permitted in 200.7(B) or (C). Section 200.7(C) provides permission to use conductors with white or gray insulation where it is permanently re-identified as an ungrounded conductor. Permitted methods of re-identification include the use of marking tape, painting or other effective means.
It is important to note that this re-identification of the white or gray insulation must occur at the switch location and all locations where the gray or white conductor is visible and accessible. The most common method to re-identify is with marking tape (other than white, gray or green) that must encircle the conductor. This requirement also mandates that, where the white or gray conductor is used as a switch leg, the conductor may be used for the supply to the switch. However, it is never permitted as a return from the switch to a lighting fixture or other switched outlet.
The reason for the marking is to identify the white or gray conductor as an ungrounded conductor. It should be noted that this permissive requirement is not limited to switch legs.
When applying the rules for ground-fault circuit interrupter (GFCI) protection of receptacles in dwelling-unit basements, Section 210.8(A)(5) refers to portions or areas of the basement not intended as habitable rooms. How do I determine the intent of a room? My neighbor recently had her basement finished by a local contractor. The electrical inspector required all of the 125-volt (V) receptacles to be GFCI-protected. He said the room was not habitable as per the building code.
Rooms do not have intent as to how they will be occupied. However, we can look at a room or space and determine how the builder intended the space to be occupied and other potential uses for the room. The 2017 NEC no longer contains a reference to storage areas, work areas and similar areas as being unfinished spaces. The requirement for GFCI protection in Section 210.8(A)(5) now simply requires GFCI protection of all 125V, single-phase, 15- and 20-ampere (A) receptacles in unfinished portions or areas of the basement not intended as habitable rooms.
This ties us directly to the building code definition of “habitable space,” which is spaces for living, sleeping, eating or cooking. That sounds easy, but it’s not unless you are well versed in building-code requirements.
The requirements for habitable space include, but are not limited to, minimum ceiling height, ventilation/windows based on a percentage of floor area, minimum room size, lighting and egress. The inspector apparently saw an issue with the finished basement and determined it did not meet the requirements for a habitable space, per the building code. While a basement area may seem completely finished as a living space, it may not meet all building code requirements for a habitable space.
Branch circuit or a feeder?
Perhaps you can provide an answer to a debate we have been having over the correct NEC term for conductors. Per the contract drawings, we wired multiple large industrial heaters with 4 AWG copper conductors protected at 100A from a panelboard to a fused disconnect (with current limiting fuses rated at 100A) at the equipment location. We then installed 4 AWG copper conductors in flexible metal conduit from the fused disconnect to the heaters. Since there is no outlet, are the conductors from the panelboard to the fused disconnect located at the equipment branch-circuit conductors or feeders?
The conductors from the panelboard to the fused disconnect at the equipment are feeders. The conductors from the fused disconnect to the equipment are branch-circuit conductors. Article 100 defines branch-circuit conductors as the conductors between the final overcurrent device protecting the circuit and the outlet(s).
There is an outlet in this installation. As defined in Article 100, an outlet is a point on the wiring system at which current is taken to supply utilization equipment. The point at which a branch circuit is hard-wired to utilization equipment is an outlet by definition.
Service lateral or underground service conductors?
Why did the NEC change the name of service conductors installed underground from a “service lateral” to “underground service conductors”?
A name change did not occur here. A new definition was added in the 2011 NEC revision cycle to clearly differentiate between underground service conductors that the NEC covers and those it does not.
Article 100 contains two definitions for service conductors installed underground. The first is “service lateral,” which is the underground conductors from the serving electric utility to the service point. The utility owns these conductors, and they are not considered part of the “premises wiring.” Service lateral conductors are not within the scope of the NEC as seen in Section 90.2(B)(5)(a).
The second defined term is “underground service conductors.” Those begin at the service point and are installed to the first point of connection, which is typically in a meter enclosure. Underground service conductors are within the NEC scope. They are part of the premises wiring and are subject to all applicable NEC requirements.
It is not unusual for a utility to take service lateral conductors into a handhole enclosure just inside the property line and end there. An electrical contractor then installs underground service conductors (which the NEC covers) from the handhole enclosure (the service point) to a meter location to supply a building or structure.
Hotel room receptacles
Is it permissible to locate the receptacles in a hotel room so that there is one on each side of the bed, leaving larger spaces elsewhere? The architectural drawings locate receptacles in a manner that seems to be in conflict with the NEC. The requirements of Section 210.52(A) are not completely met. Are these receptacles required to be arc-fault circuit interrupter (AFCI) protected?
The NEC permits receptacle placement in guest rooms and guest suites to be modified to suit the room. Section 210.60(A) requires guest rooms and suites to have receptacle outlets installed in accordance with 210.52(A), which mandates the number of required outlets and the outlet spacing.
Section 210.52(D) also applies, since it requires at least one receptacle outlet be installed in bathrooms within three feet of the outside edge of each basin. Meanwhile, Section 210.60(B) addresses the placement of receptacle outlets in guest rooms and guest suites.
The total number of receptacle outlets is determined by the requirements of 210.52(A), but the locations of the outlets are permitted to be modified in order to work with the permanent layout of furniture in the rooms. In all guest rooms and guest suites, at least two of the receptacle outlets must be readily accessible.
A revision in the 2017 NEC adds a new Section 210.12(C). This section requires all 120V, single-phase, 15- and 20A branch circuits supplying receptacle, lighting or other outlets and devices in guest rooms or suites to be AFCI-protected.
Why are marking requirements spread out all over the NEC? In my opinion, application of marking and labeling requirements would be best located in Article 100 for general requirements. For example, if we consider a panelboard, there may be three or more separate requirements in different articles requiring some type of marking. What is the difference between a marking and a label? Which is permanent?
Marking requirements in the NEC are properly located with the associated rule that drives the mark or label. In many cases, a panelboard (for example) may exist. The addition of another system or branch circuit to the panelboard may drive a new marking requirement. Having that requirement located with the associated rule increases usability.
I agree that a panelboard may need to be marked in accordance with multiple requirements that are spread out all over the Code. I suggest you submit a public input to correlate these marking requirements. Perhaps you can propose an informational note to follow Section 408.4 containing all other marking requirements that may apply to panelboards.
Where the NEC requires a marking, there are many options. It could be a symbol or text that may be stamped, etched, written or labeled. Where the NEC requires a label, it is typically field-applied. Where the marking is required to be permanent, the intent is for a lasting marking that will remain unchanged indefinitely. Many marking requirements prohibit them from being handwritten, and others require labels that are suitable for the environment in which they are installed.
About The Author
DOLLARD is retired safety coordinator for IBEW Local 98 in Philadelphia. He is a past member of the NEC Correlating Committee, CMP-10, CMP-13, CMP-15, NFPA 90A/B and NFPA 855. Jim continues to serve on NFPA 70E and as a UL Electrical Council member. Reach him at [email protected].