Code Change Summary: Protection for insulated conductors 4 AWG or larger must now be installed before installing the conductors.
One of the most common inspector red tag items after wires are pulled is to request an insulated bushing on the end of a raceway or fitting where 4 AWG or larger insulated conductors enter an enclosure. Before hinged electrical fittings became available (see image), the electrician’s heart would sink when the electrical inspector requested a bushing on a conduit containing large conductors that were difficult to wrestle into place and terminate. To comply with the red tag, the electrician knew he had to take all the conductors loose from their termination and slide a bushing over them to thread on to the raceway, and then re-terminate all the conductors before the work could be re-inspected.
In the 2023 NEC®, Section 300.4(G) was revised to make it clear that insulated conductor’s size 4 AWG and larger require protection from abrasion where entering a cabinet, enclosure, box, or raceway BEFORE the conductors are pulled or installed. Section 300.4(G) permits the following as suitable protection methods for these conductors:
(1) An identified fitting with a smoothly rounded insulating surface
(2) A listed metal fitting with smoothly rounded edges
(3) Separating the conductors from the raceway or fitting using identified insulating material that is securely fastened in place
(4) Threaded hubs or bosses that provide a smooth rounded or flared entry for conductors and are integral to a cabinet, box, enclosure, or raceway
This code change might not be well received by the electrician since it has become common practice to install a protective bushing on the end of a raceway after the conductors have been pulled in order to avoid damaging the bushing during the wire pull. The train of thought behind the code change proposal was that if there is fear of damaging the protective bushing during the wire pull then what happens to the actual conductors without the protective bushing in place during the wire pull?
Until now, the NEC® has never addressed when, or at what stage of the installation process a protective fitting must be installed.
The protection methods mentioned in Section 300.4(G) intend to protect the conductor insulation from potential damage that can occur at the initial time of installation, as well as long term damage from the pressure between the conductor and the fitting.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC® edition of NFPA 70.
2020 Code Language:
300.4(G) 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 in accordance with any of the following:
(1) 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 using an identified insulating material that is securely fastened in place
(4) Threaded hubs or bosses that are an integral part of a cabinet, box, enclosure, or raceway providing a smoothly rounded or flared entry for conductors
2023 Code Language:
300.4(G) Fittings. Where raceways contain 4 AWG or larger insulated circuit conductors, and these conductors enter a cabinet, a box, an enclosure, or a raceway, prior to the installation of conductors, the conductors shall be protected in accordance with any of the following:
(1) 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 using an identified insulating material that is securely fastened in place
(4) Threaded hubs or bosses that are an integral part of a cabinet, box, enclosure, or raceway providing a smoothly rounded or flared entry for conductors
Based on the 2023 NEC, which of the following is true?
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