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 codefaqs@gmail.com. Answers are based on the 2017 NEC.

GFCI in locker rooms

Ground-fault circuit interrupter (GFCI) requirements for other than dwelling units include locker rooms with associated showering facilities. How do I determine if showering facilities are indeed “associated” with locker rooms? On a large high school project, we installed 15-ampere (A), 120-volt (V) receptacles in six separate locker rooms on the ground floor. Two locker rooms, adjacent to the pool and had showers next to the locker rooms. Four others were near the gym and weight rooms, not next to showers. Did each locker room require that we comply with 210.8(B)?

No, Section 210.8(B)(7) requires GFCI protection of receptacles in locker rooms with associated showering facilities. The NEC does not define “associated” because it is generally understood. As used in this requirement, only locker rooms that are connected to showering facilities are included.

Invasive procedures

The 2017 NEC has a new definition in Article 517 of the term “invasive procedure.” How does this affect the requirements in Article 517? I could not find any requirement that applies to an invasive procedure.

The definition of “invasive procedure” is extracted from NFPA 99, Health Care Facilities Code. You are correct that no Article 517 requirement uses the term. However, it is used in an informational note that follows critical-care (Category 1) space in the definition of patient-care space. A critical-care space, as described in the informational note, includes anywhere a patient may be subjected to invasive procedures. This definition provides necessary clarity. For example, placement of peripheral intravenous needles (including flu shots) or catheters used to administer fluids are explained in the informational note, not invasive procedures and would not invoke requirements for a critical care (Category 1) space. 

Always sized at 115 percent?

Where a generator is installed to supply an optional standby system, does the Code require conductors to each circuit breaker to be sized at 115 percent of the nameplate current value on the generator? The drawings for this project show 500 kcmil copper feeder conductors from a 400A main circuit-breaker supplied with the generator into a wireway. Two 200A circuit-breaker enclosures are supplied from tap conductors at the wireway. The inspector is requiring conductors sized at 115 percent of the nameplate current to supply each of the 200A circuit-breaker enclosures. Is he correct?

No, the requirement for conductors to be sized at 115 percent of the generator nameplate current value applies only to conductors from the generator output terminals to the first overcurrent protective device (OCPD). Additionally, new Section 445.13(B) specifically permits feeder taps in accordance with 240.21(B) where the generator is equipped with a listed OCPD. 

This permission existed previously in the NEC. However, confusion and misapplication occurred due to the general rule that required conductors from generator output terminals to the first OCPD be sized at 115 percent of the generator nameplate current value.

Legally required and 
normal branch circuits

Is it permissible to install branch circuits derived from a legally required or optional standby source in the same raceway or enclosures with normal circuits? We always separate emergency-system branch circuits in raceways and cable assemblies to ensure we do not mix them with the normal source.

Yes, legally required system branch circuits may be installed in the same raceways, cables, boxes and cabinets with other wiring. Section 700.10(B) requires all wiring from an emergency source or emergency distribution overcurrent protective devices to be kept entirely independent from all other wiring and equipment (not just normal source wiring) unless specifically permitted in one of the five list items provided. Sections 701.10 and 702.10 permit legally required and optional standby system wiring to occupy the same raceways, cables, boxes and cabinets with other general (not emergency source) wiring.

SWD, HID circuit breakers

During a recent safety audit of our retail facility, we were informed that the circuit breakers we were using for turning lights on and off were not Code-compliant for switching purposes. The breakers turn on approximately 100 fluorescent-type lighting fixtures. Our insurance company instructed us to have an electrical contractor install “compliant devices.” What is required?

Section 240.83(D) of the NEC requires circuit breakers used as switches for fluorescent lighting supplied at 120V and 277V to be listed and marked as SWD or high intensity discharge (HID). Circuit breakers marked SWD are subjected to additional testing to ensure they demonstrate the capability to be used regularly as a switch for fluorescent lighting. Where the lighting being switched is HID-type lighting, circuit breakers used as switches must be marked HID. These devices are subjected to more rigorous testing due to the higher inrush current created by HID-type lighting.

Service drop or overhead 
service conductors?

The local utility installed overhead service conductors from a pole in the yard to the side of the home we were wiring. Where the conductors pass over the peak of the garage roof, they are only 5 feet from the roof. The inspector would not give us a final inspection until that was rectified. We did not install those conductors. It was not until the homeowner went to the township and complained that we were able to work this out. Are we responsible for conductors the utility installs?

No, the conductors in question are “service drop conductors” not “overhead service entrance conductors” and are not under the purview of the NEC. Article 100 contains multiple definitions that must be understood to supply Article 230 properly. The conductors you describe are service drop conductors and are not covered by the NEC because they are installed by the utility between their supply system and the service point.

Article 230 does not contain requirements for service drop conductors. Part II of Article 230 contains requirements for overhead service entrance conductors. For example, where an electric utility brings service drop conductors onto a property and they end on a pole, that is the service point. If conductors are extended from that point overhead to another pole, building or structure, they are premises wiring and are defined as overhead service entrance conductors covered by the NEC. Section 230.24(A) requires overhead service conductors to be installed with a minimum clearance of 8 feet over a roof. When applying Article 230 Services, it is imperative to understand at a minimum the following definitions: premises wiring, service, service point, service drop, service lateral, overhead service entrance conductors, underground service entrance conductors, and service conductors.

Fire pump dedicated feeder

The service voltage in our area for large commercial occupancies is typically 4,160 or 13,200V. It is typical to see a high- voltage switch supplying only a smaller transformer with a secondary voltage of 480/277 or 208/120 to supply a fire pump controller, fire pump and associated equipment. Why do designers ignore overcurrent protection of the transformer secondary conductors feeding the fire pump as required by 240.21(C)? We provide secondary overcurrent protection for all other transformer secondary conductors. Why not here?

Secondary overcurrent protection of transformers and protection of transformer secondary conductors installed as a dedicated feeder to supply a fire pump is prohibited. The arrangement of the NEC in Section 90.3 permits a Chapter 6 article for special equipment to modify general requirements in Chapter 2.

In general commercial applications, it is unusual to see secondary overcurrent protection of transformers applied. The primary is typically protected at 125 percent of the transformer primary current, and secondary overcurrent protection is not required per Section and Table 450.3(B). The protection is typically installed (as you stated) to protect the secondary conductors and is installed where the transformer secondary conductors terminate as required by Section 240.21(C). This results in an OCPD and disconnecting means for the transformer secondary conductors, and this additional disconnect is prohibited in a fire pump circuit.

Section 695.3 requires reliable sources of power for electric motor driven fire pumps, and 695.3(A) lists recognized individual sources. The conductors that you describe are recognized in 695.3(A)(3) as a dedicated feeder. This is permitted where an electric utility service connection recognized in 695.3(A)(1) does not correspond with the utilization voltage of the fire pump, and it is necessary to install a transformer. Section 695.4(B)(1) permits only one (in general) disconnect between the fire pump source and equipment. Section 695.5 permits a transformer between the system supply and the fire pump controller in this installation.

Primary overcurrent protection must be sized, per 695.5(B), to carry the locked rotor current of the fire pump motor, associated pressure maintenance pumps and all accessory equipment. Secondary overcurrent protection of transformers supplying a fire pump is prohibited by Section 695.5(B). In multibuilding campus style complexes, a transformer supplying fire pump loads may supply other loads and must be installed in accordance with 695.5(C) and other specific requirements in Article 695.