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.
Hotel receptacle outlets
We are wiring a large hotel, and the engineered drawings state the individual rooms must have “receptacles installed and located in accordance with the NEC for accessibility.” We are installing the receptacles as per the architectural drawings to meet the intent of the owner. Is there more?
Yes. Guest rooms/suites in hotels, motels, sleeping rooms in dormitories, and similar occupancies are required to have receptacle outlets installed in accordance with 210.52(A) and 210.52(D). See Section 210.60. This means the spacing and number of receptacle outlets in hotel rooms must be determined in the same manner as dwelling units. It is necessary to make that determination to ensure the architectural drawings have the correct number of outlets. Section 210.52(D) requires a receptacle outlet within 3 feet of the outside edge of each basin. If the hotel room is provided with permanent provisions for cooking, all of the requirements in 210.52 must be met. Section 210.60(B) provides permission to locate the required number of receptacle outlets to accommodate the layout of permanent furniture. However, at least two receptacle outlets must remain readily accessible after the room is fully furnished. If receptacle outlets are installed behind a bed (it is a good idea to move them away), they must be located so the bed cannot contact an attachment plug, or a suitable guard must be installed.
Life safety branch
In a healthcare facility, is it permissible to place receptacle outlets that supply nurse-station computers on the life safety branch?
No. Section 517.33 provides a prescriptive list of lighting, receptacles and equipment that is permitted on the life safety branch. The following are permitted: (A) illumination for means of egress, including but not limited to corridors and passageways, stairs and approach to building exits; (B) exit signs; (C) alarms and alerting systems including fire alarm, piping system alarms and other life safety systems; (D) communications systems used for issuing instructions during emergency conditions; (E) task lighting around standby generators, battery chargers for emergency lighting, select receptacles at generators and transfer switches; (F) generator set accessories required for generator performance such as fuel transfer pumps, fans, etc.; (G) elevator cab lighting, control and communication; and (H) electrically powered doors used for egress.
Receptacle outlets that supply nurse-station computers are not permitted on the life safety branch.
Junction boxes and working space
Are junction boxes that include terminations less than 600 volts (V) considered electrical equipment? If so, are junction boxes then required to meet all of the working space requirements in 110.26?
As Article 100 defines, junction boxes containing terminations on devices or splices are considered equipment. All equipment, including but not limited to junction boxes, are not required to meet the working space requirements of Section 110.26. The requirements apply to equipment that is “likely to require examination, adjustment, servicing or maintenance while energized.”
Working space requirements for minimum distances, etc., apply only to equipment that is “likely” to require action in the future while the equipment is energized. The best example—there are many—would be a panelboard. Requiring working space in accordance with 110.26 for junction boxes is not necessary, nor is it feasible.
Bathroom 20A branch circuits
Is it permissible to supply a dwelling-unit bathroom with one or more 15-ampere (A) branch circuits if the receptacle at the sink is supplied with a 20A branch circuit? Bathrooms in many dwellings are getting bigger. They typically include a counter area for makeup or other purposes. In these larger bathrooms, we typically supply the additional outlets with 15A circuits in addition to the required 20A branch circuit. Recently, an inspector required all of the branch circuits supplying the bathroom to be rated at 20A.
The inspector is correct. Section 210.11 provides requirements for “branch circuits required,” and 210.11(C)(3) states that, in addition to the number of branch circuits required by other parts of 210.11, at least one 120V, 20A branch circuit must be provided to supply the bathroom(s) receptacle outlet(s) in dwellings. Additionally, these required circuits are not permitted to supply any other outlets. As written, this section needs work for usability, but it clearly requires all of the bathroom receptacle outlets to be supplied from one or more 20A branch circuits. The requirement is for “at least one,” but installers may provide more.
The last sentence in 210.11(C)(3) mandates that the 20A branch circuits supplying the bathroom in accordance with this requirement “shall have no other outlets.” Note that the word “circuits” is plural. The general requirement is to supply, at minimum, one 20A branch circuit. Multiple branch circuits are permitted, but they must not supply outlets outside the bathroom. The justification for 20A branch circuits is that the typical loads include hair dryers and similar appliances. The current flow of an 1,875-watt hair dryer alone can be more than 15A. Be sure to follow the 2020 NEC revision process because multiple public inputs were submitted to increase clarity and usability of this requirement.
Branches from busway
We are a vehicle parts manufacturer. In our facility, we have mechanical presses supplied by overhead busway runs that typically run the length of the building. From that busway, we have installed extra-hard-use cord with approved attachment from bus plugs, with cable-strain relief vertically down from building surface to individual presses. We have moved some of these once or twice. (I’ve been here for over eight years.) An Occupational Safety and Health Administration (OSHA) inspector wrote us up for violations of 400.10 and 400.12. The inspector claimed the equipment was permanently fixed, and we could not use cable or cord. Does this installation fall under 368.56(B) as stationary equipment under busway? Does it fall under 400.10(A)(6) to facilitate frequent interchange, and if it does, where does it say how frequently such interchange would have to occur? Why does the Code in 368.56(B) mention stationary equipment, and what would that be? I have been installing and maintaining these machines for over 25 years with this method. We have had numerous electrical and OSHA inspections with nothing said.
Branches from busways are specifically permitted in 368.56(A), which lists permitted Chapter 3 wiring methods, and in 368.56(B), which permits cord and cable assemblies. In this case, 368.56(B) permits extra-hard-use cord as a branch from busway for the connection of portable equipment or the connection of stationary equipment to facilitate their interchange in accordance with 400.10 and 400.12 and the four conditions provided. Note that the word “frequent” is not used; it is the connection of stationary equipment to facilitate their interchange. No time frame is provided.
The installation must meet the four conditions: attaching the cord or cable to the building by an approved means, the length of the cord or cable from a busway plug-in device to a suitable tension take-up support device is not more than 6 feet (the exception may apply here and you could go to 8 feet), the cord and cable is installed as a vertical riser, and strain-relief cable grips are provided for the cord or cable at the busway plug-in device and equipment terminations.
This installation is specifically permitted in 400.10, Uses Permitted, in list item (10). Since this installation is permitted, the requirements in 400.12, Uses Not Permitted, do not apply. In this case, the inspector did not understand the arrangement of the NEC and made an incorrect interpretation.
Integrated gas spacer (IGS) cable
Type IGS cable has been in the NEC for many cycles. This is just one more item in the NEC that seems to be obsolete. We cannot find a supplier or anyone that has installed this cable. Are there any practical uses for this cable?
Type IGS cable was added as a new Article in the 1984 NEC. At that time, the substantiation to support this new cable assembly explained that there was a need to lower material costs to eliminate failures on underground cables. The substantiation further explained the single conductors wrapped in kraft paper are installed in a tough natural-gas-approved pipe, which is used as a conduit. It is then pressurized with sulfur hexafluoride gas (SF6) and is kept pressurized at around 20 pounds per square inch (psi).
The substantiation further explains there were multiple installations (likely experimental) that were successful in the Oakland, Calif., area. Based upon my own limited research and personal experience, I do not know of any installation of this product other than as explained in the original substantiation to put this wiring method into the NEC. Keeping the cables pressurized with SF6 gas may have been a challenge for this product. SF6 gas is quite dense and will settle creating potentially oxygen deficient atmospheres in trenches, manholes or other spaces. SF6 is a potent greenhouse gas and is highly regulated, which may be another reason that this product has seen very limited use.