# Title 24.1 — State Electrical Board

## Article 24.1-06 — Electrical Wiring Standards

## Chapter 24.1-06-05 — Special Occupancies

### § 24.1-06-05-01. (NEC 500) Hazardous locations.

1. Classification of hazardous locations is required to be completed by owner, representative, or
engineer that has the qualifications and shall provide documentation as required by the
provisions of article 500.4, 2023 edition, National Electrical Code (1st version, printed in 2022),
including the reference standards as listed in article 500.4, 2023 edition, National Electrical
Code (1st version, printed in 2022).
2. For classifications of oilfield installations refer to API RP 500, Classification of Locations for
Electrical Installations at Petroleum Facilities, third edition, December 2012.
3. Surge arrestors shall be provided for all services in grain elevators.
4. Hot bearing or other similar detection systems shall be installed in accordance with articles
500-516, 2023 edition, National Electrical Code (1st version, printed in 2022).
History: Effective April 1, 2017; amended effective October 1, 2020; July 1, 2024.
General Authority: NDCC 43-09-05
Law Implemented: NDCC 43-09-21, 43-09-22
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### § 24.1-06-05-50. (NEC 550) Mobile home parks.

Service equipment may be installed on manufactured homes as required in article 550.32(b) if the
following requirements are met:
1. The mobile home is located on property owned by the homeowner and not in mobile home
park.
2. The mobile home is secured to a permanent foundation that complies with locally adopted
codes or the State Building Code.
History: Effective April 1, 2017; amended effective October 1, 2020.
General Authority: NDCC 43-09-05
Law Implemented: NDCC 43-09-21, 43-09-22

Short Cut
At 75o C
Voltage Drop Formulas 167o F
__________________________________________________________________________
L = length in feet, one way
I = load in amps
E = Volts
CMA = circular-mil area
K-factor = 25.8 multiplying factor for copper, 42.4 multiplying factor for aluminum at 75o C.
For three-phase circuits, use formula, then multiply the results by .86
Percent drop permissible voltage drop times voltage of circuit as follows:
5% of 120 120 x .05 = 6 volts
5% of 208 208 x .05 = 10.4 volts
5% of 240 240 x .05 = 12 volts
Examples with copper wire:
240 volts, 1,000 foot distance, 10 ampere load, 5% volt drop maximum

= 21,500 CMA minimum = #6 cu minimum
Same values as above but use #8 copper wire instead
= 15.6 volts/240 = 6.5% volt drop
120 volts, 8 ampere load, 100 foot distance, 3% volt drop maximum
= 5733 CMA minimum = #12 cu minimum
Refer to Chapter 9 Table 8 of NEC for conductor properties


Means of Egress Condensed Guide
1. Marking of means of egress. All required exits and access to exits shall be marked by readily
visible signs. For externally illuminated signs, letters shall be not less than six inches [150
millimeters] high. Internally illuminated signs shall be listed per ANSI/UL 924 which assures
proper letter size. Chevron-shaped arrows are required to indicate direction to exits. Every
sign shall be suitably illuminated. For externally illuminated signs see subsection 7.10.6, Life
Safety Code®, NFPA 101, 2015 edition through December 31, 2020, and subsection 7.10.6,
Life Safety Code®, NFPA 101, 2018 edition thereafter and for internally illuminated signs see
subsection 7.10.7.
2. Illumination of means of egress. Illumination of means of egress shall provide continuous,
dependable, illumination of not less than one foot-candle at floor level for all areas such as
corridors, stairways, and exit doorways, providing a lighted path of travel to the outside of the
building and public way during all times that the means of egress is available for use. For new
stairs, the required minimum illumination level is ten foot-candle during conditions of stair use.
Illumination shall be from a source of reasonable assured reliability and may be supplied from
normal lighting circuits or special circuits with switching controlled by authorized personnel.
Illumination required for exit marking shall also serve for illumination of means of egress and
shall be so arranged that failure of a single unit, such as burning out of a single bulb will not
leave any area in darkness.
3. Emergency lighting. Emergency lighting systems shall be so arranged to provide the required
illumination automatically in event of any interruption or failure of the normal power supply. An
acceptable alternate source of power may be an electric generator or approved battery. In
occupancies where emergency lighting is required, the circuits supplying exit marking and
illumination of means of egress shall be supplied by the emergency system. Other areas of
the facilities only requiring exit marking and illumination of means of egress may be supplied
by the normal source.
4. Classification of occupancy based on chapter 6, Life Safety Code®, NFPA 101, 2015 edition
through December 31, 2020, and chapter 6, Life Safety Code®, NFPA 101, 2018 edition
thereafter.
Note: Check with local building officials to determine occupancy and occupant load.
Assembly. Assembly occupancies include all buildings or portions of buildings used for gathering
together fifty or more persons for such purposes as deliberation, worship, entertainment, eating,
drinking, amusement, or awaiting transportation. Assembly occupancies also include special
amusement buildings regardless of occupant load.
Assembly occupancies might include the following:
Armories Libraries
Assembly halls Mortuary chapels
Auditoriums Motion picture theaters
Bowling lanes Museums
Clubrooms Passenger stations and terminals of
air, surface, underground, and marine
public transportation facilities
Colleges and university Places of religious worship
Classrooms, fifty persons and over Poolrooms
Conference rooms Recreation piers
Courtrooms Restaurants

Dance halls Skating rinks
Drinking establishments Theaters
Exhibition halls Gymnasiums
Occupancy of any room or space for assembly purposes by fewer than fifty persons in a building or
other occupancy and incidental to such other occupancy shall be classified as part of the other
occupancy and shall be subject to the provisions applicable thereto.
Educational. Educational occupancies include all buildings or portions of buildings used for educational
purposes through the twelfth grade by six or more persons for four or more hours per day or more than
twelve hours per week.
Educational occupancies include the following:
Academies Schools
Kindergartens
Other occupancies associated with educational institutions shall be in accordance with the appropriate
part of Life Safety Code®, NFPA 101, 2015 edition through December 31, 2020, and Life Safety
Code®, NFPA 101, 2018 edition thereafter.
In cases when instruction is incidental to some other occupancy, the section of Life Safety Code®,
NFPA 101, 2015 edition through December 31, 2020, and Life Safety Code®, NFPA 101, 2018 edition
thereafter, governing such other occupancy applies. For example:
College and university classrooms under fifty persons - business occupancy
College and university classrooms fifty persons and over - assembly
Instructional building - business occupancy
Laboratories, instructional - business occupancy
Laboratories, noninstructional - industrial
Day care. Day care occupancies include all buildings or portions of buildings in which four or more
clients receive care, maintenance, and supervision, by other than their relatives or legal guardians, for
less than twenty-four hours per day.
Day care occupancies include the following:
Child day care occupancies
Adult day care occupancies, except where part of a health care occupancy
Nursery schools
Day care homes
Kindergarten classes that are incidental to a child day care occupancy
In areas when public schools offer only half-day kindergarten programs, many child day care
occupancies offer state-approved kindergarten classes for children who require full day care. As these
classes are normally incidental to the day care occupancy, the requirements of the day care occupancy
should be followed.
Health care. Health care occupancies are those used for purposes such as medical or other treatment
or care of persons suffering from physical or mental illness, disease, or infirmity and for the care of
infants, convalescents, or infirm aged persons. Health care occupancies provide sleeping facilities for
four or more occupants and are occupied by persons who are mostly incapable of self-preservation

because of age, physical or mental disability, or because of security measures not under the occupants'
control.
Health care occupancies include the following:
Hospitals
Nursing homes
Limited care facilities
Ambulatory health care. Ambulatory health care occupancies are those used to provide services or
treatment simultaneously to four or more patients on an outpatient basis. The patients are considered
incapable of self-preservation due to the treatment rendered, the use of anesthesia, or the injury for
which they are receiving emergency or urgent care.
Detention and correctional. Detention and correctional occupancies are used to house individuals
under varied degrees of restraint or security and are occupied by persons who are mostly incapable of
self-preservation because of security measures not under the occupants' control.
Detention and correctional occupancies include the following:
Adult and juvenile substance abuse centers
Adult and juvenile work camps
Adult community residential centers
Adult correctional institutions
Adult local detention facilities
Juvenile community residential centers
Juvenile detention facilities
Juvenile training schools
Residential. Residential occupancies are those occupancies in which sleeping accommodations are
provided for normal residential purposes and include all buildings designed to provide sleeping
accommodations.
Exception. Those classified under health care or detention and correctional occupancies.
Residential occupancies are treated separately in Life Safety Code®, NFPA 101, 2015 edition through
December 31, 2020, and Life Safety Code®, NFPA 101, 2018 edition thereafter, in the following groups:
One-family and two-family dwelling unit
Lodging or rooming house
Hotels
Dormitory
Apartment building
Residential board and care occupancy
Mercantile occupancy. An occupancy used for the display and sale of merchandise.
Mercantile occupancies include the following:
Auction rooms Restaurants with fewer than
fifty persons
Department stores Shopping centers
Drugstores Supermarkets

Office, storage, and service facilities incidental to the sale of merchandise and located in the same
building should be considered part of the mercantile occupancy.
Business. Business occupancies are those used for the transaction of business other than those
covered under mercantile.
Business occupancies include the following:
Air traffic control towers (ATCTs) Doctors' offices
City halls Townhalls
College and university instructional General offices
buildings, classrooms under fifty
persons, and instructional laboratories
Courthouses Outpatient clinics, ambulatory
Dentists' offices
Doctors' and dentists' offices are included unless of such character as to be classified as ambulatory
health care occupancies.
Industrial. Industrial occupancies include factories making products of all kinds and properties devoted
to operations such as processing, assembling, mixing, packaging, finishing or decorating, and
repairing.
Industrial occupancies include the following:
Dry cleaning plants Power plants
Factories of all kinds Pumping stations
Food processing plants Refineries
Gas plants Sawmills
Hangars (for servicing or maintenance) Telephone exchanges
Laundries
In evaluating the appropriate classification of laboratories, the authority having jurisdiction should
determine each case individually based on the extent and nature of the associated hazards. Some
laboratories may be classified as occupancies other than industrial, for example, a physical therapy
laboratory or a computer laboratory.
Storage. Storage occupancies include all buildings or structures utilized primarily for the storage or
sheltering of goods, merchandise, products, vehicles, or animals.
Storage occupancies include the following:
Barns Hangars (for storage only)
Bulk oil storage Parking structures
Cold storage Warehouses
Freight terminals Truck and marine terminals
Grain elevators

Storage occupancies are characterized by the presence of relatively small numbers of persons in
proportion to the area. Any new use that increases the number of occupants to a figure comparable
with other classes of occupancy changes the classification of the building to that of the new use.
Multiple occupancies. A building or structure in which two or more classes of occupancy exists shall be
classified as a multiple occupancy. Multiple occupancies shall be protected either as mixed
occupancies or as separated occupancies, in accordance with subsection 6.1-14.3 or 6.1-14.4,
respectively, of Life Safety Code®, NFPA 101, 2015 edition through December 31, 2020, and Life
Safety Code®, NFPA 101, 2018 edition thereafter. Where exit access from an occupancy traverses
another occupancy, the multiple occupancy shall be protected as a mixed occupancy. In implementing
the mixed occupancies form of protection, the building shall comply with the most restrictive
requirements of the occupancies involved, unless separate safeguards are approved.
5. Occupant load factor table.
Use Square Feet per Person
Assembly use - less concentrated use 15 net*
Areas of concentrated use without fixed seating 7 net*
Waiting space 3 net*
Bleachers, pews, and similar bench-type seating Note 1
Fixed seating Note 2
Kitchens 100 gross**
Libraries
In stack areas 100 gross**
In reading rooms 50 net*
Swimming pools
Water surface 50 gross**
Pool decks 30 gross**
Exercise rooms with equipment 50 gross
Exercise rooms without equipment 15 gross
Lighting and access catwalks, galleries, and gridirons 100 net
Casinos and similar gaming areas 11 gross
Skating rinks 50 gross
Stages 15 net*
Educational use
Classroom area 20 net*
Shops, laboratories, and similar vocational areas 50 net*
Day care use
Maximum number of persons intended to occupy that floor, 35 net*
but not less than
Health care use
Sleeping departments 120 gross**
Inpatient departments 240 gross**
Ambulatory health care 150 gross**
Detention and correctional use

Maximum number of persons intended to occupy that floor, 120 gross**
but not less than
Residential use
Hotels, motels, dormitories, apartment buildings:
Maximum probable population, but not less than 200 gross**
Residential board and care use Note 3
Mercantile use (including malls)
Street level and below (sales) 30 gross**
Sales area on two or more street floors 40 gross
Upper floor (sales) 60 gross**
Storage, receiving, or shipping (not open to the general 300 gross**
public)
Assembly areas See "Assembly"
Business use (other than below) 150 gross**
Concentrated business use 50 gross**
Air traffic control tower observation levels 40 gross**
Collaboration rooms/spaces ≤ 450 ft2 (41.8 m2) in area 30gross
Collaboration rooms/spaces > 450 ft2 (41.8 m2) in area 15 gross
Other purposes Note 4
Industrial use
General and high hazard industrial 100 gross**
Special purpose industrial N/A
Storage use
In storage occupancies N/A
In mercantile occupancies 300 gross**
In other than storage and mercantile occupancies 500 gross**
* Net floor area is the actual occupied area, not including accessory unoccupied areas or
thickness of walls.
** Gross floor area is the floor area within the inside perimeter of the outside walls of the
building under consideration with no deduction for hallways, stairs, closets, thickness of
interior walls, columns, or other features.
Notes to occupant load table.
Note 1. Bleachers, pews, and similar bench-type seating: one person per eighteen linear
inches.
Note 2. Fixed seating. The occupant load of an area having fixed seats shall be determined
by the number of fixed seats installed. Required aisle space serving the fixed seats shall not
be used to increase the occupant load.
Note 3. Refer to chapters 32 and 33 of Life Safety Code®, NFPA 101, 2015 edition through
December 31, 2020, and chapters 32 and 33 of Life Safety Code®, NFPA 101, 2018 edition
thereafter.
Note 4. Occupant load factors associated with the use.
6. Building classification table.

x - indicates required
o - indicates not required
Marking of
Means Illumination of Emergency
Occupancy Egress Means Egress Lighting
Assembly x x x
Educational x x x
Day care x x x
Interior stairs and corridors x x x
Assembly use spaces x x x
Flexible and open plan buildings x x x
Interior or limited access portions of buildings x x x
Shops and laboratories x x x
Family day care homes (more than three but fewer o x o
than seven persons)
Group day care homes (seven to twelve persons) o x o
Health care occupancies (Note 1) (for complete x x x
details see article 517 of NEC and NFPA
standard 99)
Detention and correctional x x x
Residential
Hotels and dormitories x x x Note 2
Apartment buildings
Twelve or less apartments x x o Note 3
More than twelve apartments or greater than x x x Note 3
three stories in height
Residential board and care
More than sixteen residents x x x Note 2
Mercantile
Class A - Over thirty thousand square feet x x x
[2787.09 square meters] or greater than three
stories
Class B - Three thousand square feet to thirty x x x
thousand square feet [278.71 square meters to
2787.09 square meters] or three thousand
square feet [278.71 square meters] or less and
two or three stories
Class C - Under three thousand square feet x Note 5 x o
[278.71 square meters] and one story
Malls x x x
Business x x o
Three or more stories in height x x x
Fifty or more persons above or below level of exit x x x
discharge

Three hundred or more persons x x x
All limited access and underground x x x
Industrial x x Note 6 x Note 6 and 7
Storage x x Note 8 x Note 8 and 9
Special structures (refer to chapter 11, Life Safety Code®, NFPA 101, 2015 edition through
December 31, 2020, and chapter 11, Life Safety Code®, NFPA 101, 2018 edition thereafter).
Mixed occupancies (Note 5).
Note 1. Exception: Power supply for exit and emergency lighting shall conform to NFPA 110.
Note 2. Exception: Where each guest room, guest suite, or resident sleeping room has an exit direct
to the outside of the building at street or ground level emergency lighting is not required.
Note 3. Exception: Buildings with only one exit need not be provided with exit signs.
Note 4. Exception: Where the same means of egress serve multiple use or combined occupancies,
exit lighting, exit signs, and emergency lighting shall be provided for the occupancy with the most
stringent lighting requirements. The occupant load of each type of occupancy shall be added to arrive
at the total occupant load.
Note 5. Exception: Where an exit is immediately apparent from all portions of the sales area, the exit
marking is not required.
Note 6. Exception: Special purpose industrial occupancies without routine human habitation.
Note 7. Exception: Structures occupied only during daylight hours, with skylights or windows arranged
to provide the required level of illumination on all portions of the means of egress during these hours.
Note 8. Exception: Storage occupancies do not require emergency lighting when not normally
occupied.
Note 9. Exception: In structures occupied only during daylight hours, with skylights or windows
arranged to provide the required level of illumination of all portions of the means of egress during
these hours, emergency lighting is not required.

Fire Alarm System Condensed Guide
All signaling devices for all occupancies shall meet Americans with Disabilities Act (ADA) requirements
(check ADA requirements).
Smoke alarms in hotels, motels, and apartments are not to be tied to the central alarm system (alarm in
room or apartment only).
Central alarm trouble indicator shall be located where it will be heard.
Systems with two or more zones shall have an annunciator panel located at an entrance approved by
the local fire department.
Cities shall have additional or more stringent requirements.
Be aware the table is the minimum and the owner or designer shall ask for more.
