Insulating plastic bushing?


Senior Member

From 2011 Handbook

300.4(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.

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.
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Senior Member
Suppose the cable is a cable like SER

Suppose the cable is a cable like SER

SER entering a box with a cable clamp