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 firstname.lastname@example.org. Answers are based on the 2017 NEC.
Does 110.26(C)(3) apply?
We have a question that just won’t seem to go away. The local inspector is insisting that 400-ampere (A) fused disconnects installed in a 2,000A vertical busway in a commercial mid-rise requires working space in accordance with 110.26(C)(3). The inspector insists the busway and disconnect are considered to be a single piece of equipment. Does 110.26(C)(3) apply in this installation?
This is a very interesting question. I was personally involved through the submission of public proposals and comments in the restructuring of 110.26(C) over multiple revision cycles, which created second level subdivision (C)(3) Personnel Doors and a reduction of the ampacity threshold from 1,200 to 800A. This requirement was located together with the requirement for large equipment rated 1,200A or more and over 6 feet wide requiring one entrance to and egress from the required working space at each end.
These requirements were separated in the 2008 revision cycle, and the requirement for personnel doors remained at 1,200A in 110.26(C)(3). In the 2014 revision cycle, the requirement for personal doors was reduced to 800A. The intent of this requirement is to recognize the need for installer/maintainers to have immediate egress capability in electrical rooms that contain larger equipment to escape the extreme thermal energy, hazardous gases and other hazards that accompany an arc flash/blast. The 800A threshold was specifically chosen in proposal 1-143a to limit the application of this requirement with high-rise buildings containing busway installations in mind. The focus at that time was on a busway installation, and the determination of applicability was the rating of the busway switch.
A busway does not and cannot contain overcurrent devices, switching devices or control devices. The ampere rating of the busway switch mounted on the busway is the trigger for the application of 110.26(C)(3). An informational note providing the Code user with additional background would be extremely helpful in this requirement’s application.
At what point does the grandfathering start and stop on a noncommercial service change? I’m a licensed electrician in my state. I’ve been told it’s up to the authority having jurisdiction (AHJ).
The NEC applies to the installation and removal of electrical conductors and raceways etc. as required in the document scope in 90.2(A) Covered. Existing installations are not required to be brought into compliance with changes in later NEC editions unless the installation is modified. Where a service is upgraded in a noncommercial structure, such as a dwelling unit, all of the NEC requirements adopted at that time will apply.
For example, the electrical installation in a dwelling unit may have been in accordance with the 1981 NEC. If the service equipment is replaced in 2019 and the local municipality has adopted the 2017 NEC, the applicable requirements in the 2017 NEC will apply to the service replacement. The AHJ must enforce the applicable NEC requirements and is not permitted to pick and choose which requirements they will enforce and those that they will ignore. However, Section 90.4 Enforcement permits the AHJ to waive specific requirements or to permit alternative methods by special permission where it is assured that equivalent objectives can be achieved by establishing and maintaining effective safety. It is important to note that Article 100 defines special permission as the written consent of the AHJ. When and where NEC requirements are waved or the AHJ permits alternative methods, the installer must receive special permission in writing from the AHJ and retain the documentation.
GFCI or GFPE?
My question is in regard to ground-fault circuit interrupter (GFCI) protection for personnel versus equipment protection in a commercial kitchen. In an effort to avoid nuisance tripping of a commercial cord-connected oven, the general contractor wants to use a 30-milliampere (mA) equipment GFCI circuit breaker. My contention is that GFCI protection in a kitchen is for personnel protection; therefore, the 5-mA GFCI circuit breaker must be used.
You are correct. GFCI protection is required. The requirement you reference is 210.8(B) Other Than Dwelling Units. This requires all single-phase receptacles rated 150 volts (V) to ground or less, 50A or less and three-phase receptacles rated 150V to ground or less, 100A or less installed in kitchens in other than dwelling units (210.8(B)(2)) to be provided with GFCI protection for personnel.
It is extremely important that all Code users are familiar with and understand the definition of GFCI in Article 100. This definition clarifies that a GFCI is a device intended for the protection of personnel that functions to de-energize a circuit or a portion of a circuit when the current to ground exceeds the values established for a Class A device. An informational note below this definition explains a Class A GFCI will trip when the current to ground is 6 mA or higher but will not trip when the current to ground is less than 4 mA.
In your question, you reference a GFCI at 30 mA. Ground-fault protection at 30 mA is not GFCI protection. It is ground-fault protection of equipment (GFPE) and does not provide protection for personnel.
Equipment protection in the NEC
After being in the electrical contracting business for over 20 years, I decided to help out and teach some classes at the local JATC. I am amazed at what I learn from some of the questions they ask. A student recently asked me if NEC requirements for overcurrent protective devices (OCPDs) are intended to protect the equipment supplied. My response was that they will provide a level of protection. What is the intent of overcurrent protection requirements in the NEC?
General requirements for overcurrent protection are in Article 240. Article 100 defines an overcurrent as “Any current in excess of the rated current of equipment, or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.” Article 240’s general requirements are to protect conductors. Supplementary overcurrent protection is permitted to be used for luminaires, appliances and other equipment or for internal circuits and components of equipment to provide additional protection for equipment. Supplementary overcurrent protection is not permitted to be used as a substitute for required branch circuit overcurrent device. See section 240.10 Supplementary Overcurrent Protection.
Article 100 defines a branch circuit overcurrent device as being capable of providing protection for service, feeder and branch circuit conductors and equipment over the full range of overcurrents between rated current and the interrupting rating of the device.
This definition clarifies that overcurrent protective devices do provide some level of protection for equipment. However, the general rules are focused on the protection of conductors. The NEC supplements Article 240 requirements with overcurrent protection requirements in other articles including but not limited to Article 430 Motors. Many installations require current limiting OCPDs to protect the equipment. We must always remember NEC requirements are the minimum, meaning the least you can do. Where or when a designing engineer or an owner desires additional protection for their equipment, it is permitted.
Electrically powered pool lifts
This year, I noticed an electrically powered pool lift was installed at our local swim club. Does the Code now require these? What Code requirements apply?
The NEC does not require electrically powered pool lifts. These pool lifts are typically installed in public or commercial pools as required by the Americans with Disabilities Act (ADA). The NEC does contain requirements for the installation of electrically powered pool lifts in Part VIII of Article 680. These lifts are defined in 680.2 as an electrically powered lift that provides accessibility to and from a pool or spa for people with disabilities. Other parts of Article 680 do not apply to pool lifts.
The general rule is that these lifts must be listed, labeled and identified for swimming pool and spa use. Pool lifts connected to premises wiring and operated above the low-voltage contact limit must be GFCI protected. Bonding is required in accordance with 680.26(B)(5) and (B)(7). This requires bonding for metal fittings attached to the pool structure unless they are not over 4 inches in any dimension and do not penetrate into the pool structure more than 1 inch and bonding of fixed metal parts. Where bonding of pool lifts is required, it will typically be with solid copper not smaller than 8 AWG.
I have personally seen many of these pool lifts installed in hotels. In each installation, the pool lift was supplied by a battery that can be removed and charged in an area remote from the pool or spa. It is important to note that Section 110.3(B) applies, and listed or labeled pool lifts must be installed and used in accordance with any instructions included in the listing or labeling. See the associated product standard, UL 60335-2-1000, the Standard for Safety for Household and Similar Electrical Appliances: Particular Requirements for Electrically Powered Pool Lifts.