Amendments to the electrical sections of the International Residential Code for One- and Two-Family Dwellings.
Metropolitan Code of Nashville and Davidson County § 16.20.154
in effect16.20.154 - Amendments to the electrical sections of the International Residential Code for One- and Two-Family Dwellings.
The following amendments, deletions or additions to the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings are hereby adopted by reference as fully as though copied into said dwelling code and thereby made a part of the one- and two-dwelling code.
Chapter 2 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by deleting the definition of Authority Having Jurisdiction and substituting the following:
Authority Having Jurisdiction - The Director of the Metropolitan Department of Codes Administration. [art. 100]
A. Section R314 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is hereby amended by deleting Section R314 and substituting the following:
R314 Smoke Detectors
New Construction
Dwelling Units and Sleeping Rooms: Approved single-station or multiple-station smoke detectors shall be installed in accordance with NFPA 72, Chapter 2, within every dwelling and every dwelling unit within an apartment house, condominium or townhouse, and every guest or sleeping room in a motel, hotel, dormitory, and sleeping rooms in residential care/assisted living occupancies. Where more than one detector is required to be installed within an individual dwelling unit, the detectors shall be interconnected, either by hardwire or listed wireless detectors, in such a manner that the actuation of one alarm will actuate all the alarms in the individual unit.
Locations Within Structures: In dwelling, dwelling units, dormitories, and sleeping rooms in residential care/assisted living occupancies smoke detectors shall be installed in each sleeping room, outside of each separate sleeping area in the immediate vicinity of the bedrooms, on each additional story of the dwelling, basements, cellars and attached garages but not including crawl spaces and uninhabitable attics. Smoke alarms shall be installed not less than 3 feet horizontally from the door or opening of a bathroom that contains a bathtub or shower unless this would prevent placement of a smoke alarm required by this section.
Installation Near Cooking Appliances: Smoke alarms shall not be installed in the following locations unless this would prevent placement of a smoke alarm in a location required by Section 314.3.
(1) Ionization smoke alarms shall not be installed less than 20 feet horizontally from a permanently installed cooking appliance.
(2) Ionization smoke alarms with an alarm-silencing switch shall not be installed less than 10 feet horizontally from a permanently installed cooking appliance.
(3) Photoelectric smoke alarms shall not be installed less than 6 feet horizontally from a permanently installed cooking equipment.
Additional Split-Level Requirements: Within every dwelling and every dwelling unit within an apartment house, condominium or townhouse, and every guest or sleeping room in a motel, hotel, dormitory, and sleeping rooms in residential care/assisted living occupancies, with split levels, a smoke detector needs to be installed only on the upper level, provided the lower level is less than one full story below the upper level, except that if there is a door between levels, then a detector is required on each level. All detectors shall be interconnected such that actuation of one alarm will actuate all the alarms in the individual unit and shall provide an alarm, which will be audible in all sleeping areas.
Power source: Smoke alarms shall receive their primary power from the building wiring when such wiring is served from a commercial source, and when primary power is interrupted, shall receive power from a battery. Wiring shall be permanent and without a disconnecting switch other than those required for overcurrent protection.
Exception 1: Smoke alarms shall be permitted to be battery operated when installed in buildings without commercial power.
Exception 2: Smoke alarms installed during alterations, repairs and additions shall be permitted to be battery powered.
Alterations, Repairs, Additions and Reconnection of Existing Services
Alterations, Repairs, Additions and Reconnection of Existing Services: When interior alterations, repairs, additions requiring a permit occur, or when electrical reconnections to an existing service requiring a permit occur, or when one or more sleeping rooms are added or created, or where interior service equipment is replaced or upgraded under non-emergency conditions in existing dwellings, the individual dwelling unit shall be equipped with interconnected smoke alarms located as required for new dwellings. For the purpose of this section, the smoke alarms shall be permitted to be wirelessly interconnected and shall be permitted to battery powered.
Exception 1: Work involving the exterior surfaces of dwellings, such as the replacement of roofing or siding, or the addition or replacement of windows or doors, or the addition of a porch or deck, are exempt from the requirements of this section.
Exception 2: Installation, alteration or repairs of plumbing or mechanical systems are exempt from the requirements of this section.
Exception 3: Work involving service entrance repairs made under emergency conditions are exempt from the requirements of this section.
Alterations, repairs and additions shall be defined as the following:
Alteration — Any construction, retrofit or renovation to an existing structure other than repair or addition that requires a permit. Also, a change in the building, electrical, gas, mechanical or plumbing system that involves an extension, addition or change to the arraignment, type or purpose of the original installation that requires a permit.
Repair — The reconstruction, replacement or renewal of any part of an existing building for the purpose of its maintenance or to correct damage.
Addition — An extension or increase in floor area, number of stories or height of a building or structure.
B. Chapter 34 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following:
For residential and commercial buildings, electrical power shall be supplied to the building in order for the inspector to perform final inspection.
Sections E3402.2 and E3402.3 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings are hereby amended by adding the following Sections E3402.2 and E3402.3:
Penetrations of Fire-Resistance-Rated Assemblies. Through penetrations of fire-resistance-rated wall or floor assemblies shall comply with Sections E3402.2 or E3402.3 Exception: Where the penetrating items are steel, ferrous or copper pipes or steel conduits, the annular space shall be permitted to be protected as follows:
In concrete or masonry wall or floor assemblies where the penetrating item is a maximum 6 inches (152 mm) nominal diameter and the opening is a maximum 144 square inches (92,900 mm 1.2), concrete, grout or mortar shall be permitted where installed to the full thickness of the wall or floor assembly or the thickness required to maintain the fire-resistance rating.
The material used to fill the annular space shall prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E 119 time temperature fire conditions under a minimum positive pressure differential of 0.01 inch of water (3 Pa) at the location of the penetration for the time period equivalent to the fire-resistance rating of the construction penetrated. 2.
E3402.2 Fire-resistance-rated-rated assembly. Penetrations shall be installed as tested in the approved fire-resistance-rated assembly.
E3402.3 Penetration firestop and draftstops. Penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E 814, with a minimum positive pressure differential of 0.01 inch of water (Pa) and shall have a F rating of not less than the required fire-resistance rating of the wall or floor/ceiling assembly penetrated.
E3402.3 Membrane penetrations. Membrane penetrations shall comply with Section 300.21.1. Where walls are required to have a minimum 1 hour fire-resistance rating, recessed light fixtures shall be so installed such that the required fire resistance will not be reduced.
Exceptions: Steel electrical boxes that do not exceed 16 square inches (0.0103 m 1.2) in area provided the total area of such openings does not exceed 100 square inches (0.0645 m 2) for any 100 square feet (9.29 m 2) of fire resistant wall area. Outlet boxes on opposite sides of the wall shall be separated as follows:
By a horizontal distance of not less than 24 inches, or 1.1.
By a horizontal distance of not less than the depth of the wall cavity when the wall cavity is filled with cellulose loose-fill or mineral fiber insulation, or 1.2.
By molded fire blocking, or 1.3.
By other listed materials and methods. 1.4.
Two-hour fire-resistance-rated nonmetallic electrical outlet boxes shall be installed in accordance with their listing. 2.
C. Section E3406.12 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by deleting Section E3406.12 and substituting with the following:
Terminal Torque Confirmation. Where tightening torque is indicated as a numeric value on equipment or in installation instructions provided by the manufacture, a calibrated torque tool shall be used to achieve the indicated torque value, unless the equipment manufacture has provided installation instructions for an alternative method of achieving the required torque. It shall be the responsibility of the installer to ensure all terminations have been properly torqued. For service conductor and feeder terminations, upon torque confirmation and prior to inspection, the installer shall mark across the terminal, lug or screw with a permeant mark to verify proper torque has been applied.
D. Chapter 36 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following:
Meter Location. (1) The power supplier will determine the physical location of the meter base. (2) For multi-occupancy structures, metering equipment shall be identified to indicate the occupancy serviced.
E. Section E3601.6.2 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following:
Readily Accessible Location. The main service disconnecting means shall not be located more than five (5) feet from the point where the service conductors leave the load side of a meter base and enter a building or other structure.
F. Section E3601.7 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is hereby amended by deleting Section E3601.7 and substituting the following:
Maximum number of disconnects. The service disconnecting means shall consist of not more than six switches or six circuit breakers mounted in a single enclosure or in a group of separate enclosures of more than 225 amps. Service equipment shall have only one (1) main means of disconnecting services of 225 amps or less.
G. Section E3608.1 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is hereby amended by deleting Section E3608.1 and substituting the following:
Grounding Electrodes. All grounding electrodes specified in E3608.1.1 through E3608.1.6 that are present at each building or structure served shall be bonded together to form the grounding electrode system. Where none of these grounding electrodes are present, one or more of the grounding electrodes specified in E3608.1.3 through E3608.1.6 shall be installed and used. A minimum of one concrete encased electrode shall be in place and visible upon a service entrance inspection. The grounding electrode conductor or bonding jumper point of connection to the rebar shall be installed in an accessible interior location that is not subject to corrosion of the rebar.
Exception: Concrete-encased electrodes of existing buildings or structures shall not be required to be part of the grounding electrode system where the steel reinforcing bars or rods are not accessible for use without disturbing the concrete.
H. Section E3702.9 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is hereby amended by deleting Section E3702.9 and substituting the following:
Branch Circuit Load for Ranges and Cooking Appliances. Where installed as separate units, ovens and cooktop units shall be served by individual circuits.
I. Section E3705.5 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following:
Overcurrent Protection Handle Ties. Circuit breakers used as overcurrent protection for circuits serving devices not requiring a grounded (neutral) conductor, such as a 240V water heater, shall be multipole breakers. Single pole breakers with tie handles shall not be approved for this purpose.
J. Section E3801.2 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following:
Service Entrance Conductors. Service entrance conductors shall be installed in conduit where such conductors serve a structure with exterior walls of brick, stone, masonry, metal or metal-clad.
K. Section E3802.4 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following exception:
NM Cable Thru Bored Holes. Exception: Nonmetallic-Sheathed Cable shall not be required to be run through bored holes in unfinished basements and crawl spaces with less than four feet (4') and six inches (6") of clearance.
L. Section E3901.2.2(1) of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is amended by adding the following exception:
Wall Space. Any wall space that is 2 feet (610 mm) or more in width, (including space measured around corners), and that is unbroken at the floor line by doorways, fireplaces, and similar openings.
Exception: Receptacles shall not be required in the wall space behind doors which may be opened fully against a wall surface. Wall measurement shall begin at the edge of the door when fully opened.
M. Section E3901.4.2 and E3901.4.3 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is hereby amended by deleting Section E3901.4.2 and E3901.4.3 and substituting the following:
Countertop and Peninsular Receptacles. The installation of receptacles for island counter spaces and peninsular counter spaces below the countertop shall be optional.
N. Section E3902.16 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following exceptions:
Arc Fault Circuit Interrupters - Where Optional
Exception 1: Arc Fault Circuit Interrupters (AFCIs) shall be optional for bathrooms, laundry areas, garages, unfinished basements, which are portions or areas of the basement not intended as habitable rooms and limited to storage, work or similar area, and for branch circuits dedicated to supplying refrigeration equipment. [st]
Exception 2: Arc Fault Circuit Interrupter (AFCI) breakers shall be optional where existing service equipment or load centers are directly replaced.
Exception 3: Arc Fault Circuit Interrupter (AFCI) breakers shall be optional where existing service equipment or load centers are relocated, provided the extension of existing conductors is not more than 6 feet and does not include any additional outlets or devices. [210.12]
O. Section E3903.4 of the 2024 Edition of the International Residential Code for One- and Two-Family Dwellings is hereby amended by adding the following:
Storage or Equipment Spaces. Light fixtures in crawl spaces shall have guarded covers.
P. Chapter 40 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following:
Wiring in Barns, Outbuilding & Haymows
(1) All lighting fixtures in barns and other outbuildings shall be of the non-conductor type directly fastened to the outlet box
(2) Drop lights shall not be installed in barns or other buildings, unless specifically approved for the purpose used.
(3) All convenience receptacles in outbuildings shall be at least three (3) feet above floor level. Wiring in hay mows shall be installed in conduit or otherwise protected against mechanical injury.
Q. Section E4202.1 of the 2024 International Residential Code for One- and Two-Family Dwellings is amended by adding the following exception:
Swimming Pools. Exception: Conductors serving swimming pools which originate at a dwelling unit service equipment or sub-panel located on the interior of the dwelling unit may be installed utilizing the appropriate wiring methods contained in Chapter 3 of the 2023 edition of the National Electrical Code. The wiring method shall comply with Article 680, 2023 edition of the National Electrical Code regarding that portion of the installation on the exterior of the dwelling unit.
(Ord. BL2025-898 § 4, 2025; Ord. BL2020-458 § 4, 2020; Ord. BL2007-1373 § 8, 2007; Ord. BL2001-703 § 9, 2001; Ord. BL2000-343 § 3, 2000; Ord. 96-562 §§ 70—84, 1996)
Source: Metropolitan Government of Nashville and Davidson County, Metropolitan Code and Charter (Municode Library, library.municode.com)URL: https://library.municode.com/tn/metro_government_of_nashville_and_davidson_county/codes/code_of_ordinances?nodeId=CD_TIT16BUCO_CH16.20ELCO_ARTIIELCO_16.20.154AMELSEINRECOOMIDWFetched: 10/28/2026