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For EC&M Magazine
By Mike Holt, NEC® Consultant
Here's the follow-up to yesterday's newsletter.
This includes the answers to the questions sent, so you can see how you did.
Figure 01
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Figure 01
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For EC&M Magazine
By Mike Holt, NEC® Consultant
Here's the follow-up to yesterday's newsletter.
This includes the answers to the questions sent, so you can see how you did.
Note: The answers to these questions are based on the 2020 NEC.
Underlined text indicates a change for the 2020 NEC.
Q1. What does the NEC require for the installation of lighting outlets in dwelling units?
A1. 210.70 Lighting Outlet Requirements
210.70 Lighting Outlet Requirements
(A) Dwelling Unit Lighting Outlets. Lighting outlets must be installed in:
(1) Habitable Rooms. At least one lighting outlet controlled by a listed wall-mounted control device must be installed in every habitable room, kitchen, and bathroom area of a dwelling unit. The wall-mounted control device must be located near an entrance to the room on a wall.‚
Author's Comment:
►See the definition of Lighting Outlet in Article 100.
►See the definition of Habitable Room in Article 100.
Ex 1: In other than dwelling unit kitchens and bathroom areas, a receptacle controlled by a listed wall-mounted control device can be used instead of a lighting outlet.
Ex 2: Lighting outlets can be controlled by occupancy sensors that are in addition to a wall-mounted control device or located in a customary wall switch location and are capable of manual override.
Author's Comment:
►The Code specifies the location of the lighting outlet, but it does not specify the switch location. Naturally, you would not want to install a switch behind a door or other inconvenient location, but the NEC does not require you to relocate the switch to suit the swing of the door. When in doubt as to the best location to place a light switch, consult the job plans or ask the customer.
(2) Other Than Habitable Rooms
(1) Hallways, Stairways, and Garages. At least one wall switch-controlled lighting outlet must be installed in hallways, stairways, and garages with electric power.
(2) Exterior Entrances. For dwelling units, attached garages, and detached garages with electric power, at least one lighting outlet controlled by a listed wall-mounted control device must provide illumination on the exterior side of outdoor entrances or exits with grade-level access. A garage vehicle door is not considered an outdoor entrance or exit.
(3) Stairway. Where a lighting outlet(s) is installed in interior stairways having six risers or more, a listed wall-mounted control device for the lighting outlet(s) must be located at each floor level and at each landing level that includes an entryway.
Ex to (A)(2(1), (2), and (3): Lighting outlets for hallways, stairways, and outdoor entrances can be controlled by a remote, central, or automatic control device.
(4) Dimmer Control. Lighting outlets located in stairways [210.70(A)(2)(3)] can be controlled by a listed wall-mounted control device where there is a full range of dimming control at each switch location in accordance with 210.70(A)(2)(3).
(B) Guest Rooms or Guest Suites. At least one lighting outlet controlled by a listed wall-mounted control device must be installed in every habitable room and bathroom area of a guest room or guest suite of hotels, motels, and similar occupancies.
Ex 1: In other than bathroom areas and kitchens, a receptacle controlled by a listed wall-mounted control device is permitted.
Ex 2: Lighting outlets can be controlled by occupancy sensors that are in addition to a wall-mounted control device or located in a customary wall switch location and are capable of manual override.
(C) All Occupancies. At least one lighting outlet that contains a switch or is controlled by a wall switch or listed wall-mounted control device must be installed in attics, underfloor spaces, utility rooms, and basements used for storage or containing equipment that requires servicing.
The switch or wall-mounted control device must be located at the usual point of entrance to these spaces, and the lighting outlet must be located at each entry that permits access to the attic and underfloor space, utility room, or basement. Where a lighting outlet is installed for equipment requiring service, the lighting outlet must be installed at or near the equipment that requires servicing.
Author's Comment:
►The use of electronic wireless control devices is becoming more common and such devices are available from several manufacturers. In keeping up with technology, many of the electronic switches are addressable via WIFI as well.
►Section 210.70 introduced a new term, Wall-Mounted Control Device, that is not defined in either this article or in Article 100 but is implied to include both the traditional wall switch and the newer electronic control devices.
►It is also important to note that the lighting in these spaces may require GFCI protection as specified in 210.8.
Q2. What is the Code rule regarding the number of disconnecting means allowed for a structure fed by an outside feeder?
A2. (B) Common Supply Equipment. Where feeder conductors originate in the same panelboard, switchboard, or other distribution equipment, and each feeder terminates in a single disconnecting means, not more than six feeders are permitted. [225.30(B)],
Where more than one feeder is installed, all feeder disconnects supplying the building must be grouped in the same location. Each disconnect must be marked to indicate the load served.
Author's Comment:
►This new rule simply permits up to six feeders with individual disconnects to be used instead of a single large feeder and six disconnects at the second building. It also increases safety because multiple smaller feeders will act to reduce the arc flash hazard by reducing the incident energy.
Q3. What are the NEC marking requirements for power distribution blocks installed on service conductors?
A3. 230.46 Spliced Conductors
Service-entrance conductors can be spliced or tapped in accordance with 110.14, 300.5(E), 300.13, and 300.15 [230.46].
Pressure connectors and devices for splices and taps must be listed. Power distribution blocks installed on service conductors must be listed and marked suitable for use on the line side of the service equipment or equivalent.‚Figure 01
Note: Effective January 1, 2023, pressure connectors and devices for splices and taps installed on service conductors must be marked suitable for use on the line side of the service equipment or equivalent.
Author's Comment:
►Because power distribution blocks are secured to the enclosure, they must have the ability to withstand opposing forces so that conductors do not pull out of the terminals and potentially short circuit to each other or to ground during a short-circuit condition.
►The same opposing forces are in effect for devices used for splicing and tapping service conductors. The current product standards and testing do not evaluate for these forces and as a result, a new requirement effective (January 1, 2023) states that pressure connectors and devices for splices and taps installed on service conductors must be marked suitable for use on the line side of the service equipment or the equivalent.
►It is important to note that when the Code sites a future effective date it gives the industry manufacturers, designers, installers, and building owners an opportunity to adjust and be prepared for the anticipated change.
Q4. What is the Code requirement for the installation of barriers in service equipment?
A4. No matter how many times we are told to de-energize and never work on hot electrical equipment, there are times where shutting down is not an option. This new rule requires uninsulated service-phase busbars or terminals to be protected from inadvertent contact by barriers. This, along with the proper personal protective equipment (PPE), will help protect service technicians [230.62].
Analysis
230.62(C) Barriers. A new subsection (C) was added to require barriers to be placed in service equipment so no uninsulated, phase busbar, or terminal is exposed to inadvertent contact while servicing load side terminations. The same hazard exists in enclosed circuit breakers, transfer switches suitable for use as service equipment, enclosed switches, MCCs marked as suitable for service equipment, and industrial control panels marked as suitable for use as service equipment. This revision requires all types of service equipment to have the energized parts protected from accidental contact [230.62].
230.62 Service Equipment”Enclosed or Guarded
(C) Barriers. Barriers must be placed in service equipment so that no uninsulated, ungrounded service busbar or service terminal is exposed to inadvertent contact by persons or maintenance equipment while servicing load terminations.‚
Author's Comment:
►This new rule expands on the (now deleted) requirement that was found in 408.3(A) requiring barriers over service busbars or terminals in panelboards, switchboards, and switchgear.
Q5. What does the NEC require for surge protective devices at service equipment?
A5 This new section requiring the installation of a surge-protective device (SPD) for all dwelling unit services has been a long time coming. Up until now, dwelling unit surge protection has been optional and usually an extra for the electrician.
Analysis
This requirement is being driven by the increasing amount of sensitive electronic equipment found in dwelling units. Electronic life safety equipment such as fire alarm systems, AFCIs, GFCIs, and smoke alarms, as well as consumer electronic devices such as computers and televisions can all be damaged by voltage surges. Studies by NEMA, IEEE, and UL all show that surges cause a significant amount of damage.
The text in 230.67(B) requires the SPD to be an integral part of the service equipment or located immediately adjacent to that equipment. There is an exception that permits the SPD to be located at the next level downstream distribution equipment.
230.67 Surge Protection
(A) Surge-protective Device. All services suppling dwelling units must be provided with a surge-protective device. [230.67]
(B) Location. The surge-protective device must be an integral part of the service disconnect or be located immediately adjacent to the service disconnect.
Ex: The surge-protective device is permitted to be located in the downstream panelboard.
Author's Comment:
►An example of where the exception could be applied is where there is an exterior meter main that feeds an interior panel. The SPD could be installed at the interior panel using the exception.
►See Parts I and II of Article 242 for the installation requirements that apply to SPDs.
(C) Type. The surge-protective device must be a Type 1 or Type 2 SPD
(D) Replacement. Where service equipment is replaced, surge protection must be installed.
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