300 – General Requirements for Wiring Methods and Materials
300.4(G) – Alternative Metal Fittings: Protection Against Physical Damage
Change at a Glance:
Title was revised to remove the word “Insulated” to cover alternative metal fittings. Text added to cover listed metal fittings that have smoothly rounded edges that will not damage the 4 AWG and larger conductors.
300.4 Protection Against Physical Damage.
Where subject to physical damage, conductors, raceways, and cables shall be protected.
(G) Insulated Fittings. Where raceways contain 4 AWG or larger insulated circuit conductors, and these conductors enter a cabinet, a box, an enclosure, or a raceway, the conductors shall be protected by an identified fitting providing a smoothly rounded insulating surface, unless the conductors are separated from the fitting or raceway by identified insulating material that is securely fastened in place. in accordance with any of the following:
(1) by An identified fitting providing a smoothly rounded insulating surface
(2) A listed metal fitting that has smoothly rounded edges
(3) Separation from the fitting or raceway by using an identified insulating material that is securely fastened in place
(4) Threaded hubs or bosses that are an integral part of cabinet, box, enclosure, or raceway provide a smoothly rounded or flared entry for conductors. Exception: Where threaded hubs or bosses that are an integral part of a cabinet, box, enclosure, or raceway provide a smoothly rounded or flared entry for conductors. Conduit bushings constructed wholly of insulating material shall not be used to secure a fitting or raceway. The insulating fitting or insulating material shall have a temperature rating not less than the insulation temperature rating of the installed conductors.
300.7(A) – Sealings in Raceways Exposed to Different Temperatures
Change at a Glance:
Where raceways or sleeves are known to be subjected to different temperatures, and where condensation is known to be a problem, it is required to be sealed with a sealant identified for use with cable insulation, conductor insulation (rather than filled with an approved material).
300.7 Raceways Exposed to Different Temperatures.
(A) Sealing. Where portions of a raceway or sleeve are known to be subjected to different temperatures, and where condensation is known to be a problem, as in cold storage areas of buildings or where passing from the interior to the exterior of a building, the raceway or sleeve shall be filled with an approved material sealed to prevent the circulation of warm air to a colder section of the raceway or sleeve. Sealants shall be identified for use with cable insulation, conductor insulation, a bare conductor, a shield, or other components. An explosionproof seal shall not be required for this purpose.
300.15(F) – Boxes, Conduit Bodies, or Fittings- Where Required
Change at a Glance:
Revisions occurred to make it clear that listed transition fittings and listed interconnector devices are permitted to be installed in concealed locations behind drywall and similar locations.
300.15 Boxes, Conduit Bodies, or Fittings- Where Required.
A box shall be installed at each outlet and switch point for concealed knob-and-tube wiring. Fittings and connectors shall be used only with the specific wiring methods for which they are designed and listed.
Where the wiring method is conduit, tubing, Type AC cable, Type MC cable, Type MI cable, nonmetallic- sheathed cable, or other cables, a box or conduit body shall be installed at each conductor splice point, outlet point, switch point, junction point, termination point, or pull point, unless otherwise permitted in 300.15(A) through (L).
(F) Fitting. A fitting identified for the use shall be permitted in lieu of a box or conduit body where conductors are not spliced or terminated within the fitting. The fitting shall be accessible after installation, unless listed for concealed installation.
300.22(D) – Air-handling Areas Beneath Raised Floors for IT Rooms
Change at a Glance:
Revision to reference 645.5(E) rather than the entire Article 645 for electrical wiring in air-handling areas beneath raised floors for information technology equipment.
300.22 Wiring in Ducts Not Used for Air Handling, Fabricated Ducts for Environmental Air, and Other Spaces for Environmental Air (Plenums)
The provisions of this section shall apply to the installation and uses of electrical wiring and equipment in ducts used for dust, loose stock, or vapor removal; ducts specifically fabricated for environmental air; and other spaces used for environmental air (plenums).
(D) Information Technology Equipment. Where the installation complies with the special requirements in 645.4, electrical wiring in air-handling areas beneath raised floors for information technology equipment shall be permitted in accordance with Article 645 645.5(E).
300.25 – Exit Enclosures (Stair Towers)
Change at a Glance:
New section added pertaining to the allowable electrical wiring methods serving electrical equipment in exit enclosures (stairways).
300.25 Exit Enclosures (Stair Towers)
Where an exit enclosure is required to be separated from the building, only electrical wiring methods serving equipment permitted by the authority having jurisdiction in the exit enclosure shall be installed within the exit enclosure.
Informational Note: For more information, refer to NFPA 101-2018, Life Safety Code, 7.1.3.2.1(10)(b).
300.45 – Replacing the word “Warning” with “Danger” Signs
Change at a Glance:
Editorial revisions for signs required to be posted at points of access to conductors for raceway and cable systems of over 1000 volts replacing the word “Warning” with the word “Danger.”
300.45 Warning Danger Signs. Warning Danger signs shall be conspicuously posted at points of access to conductors in all conduit raceway systems and cable systems. The warning sign(s) shall be legible and permanent and shall carry the following wording meet the requirements in 110.21(B), shall be readily visible, and shall state the following:
DANGER—HIGH VOLTAGE—KEEP OUT