Replacement cord ends undergo UL testing and are listed or approved for uses that have passed such testing.This devices have not been approved for use with Non-metalic cable, AKA NM or ROMEX.
In this photograph, a replacement cord end has been installed on a piece of NM cable.Two other defects can be seen in this photograph.The type of NM cable used is not designed for exterior use.Sunlight and water will deteriorate the plastic sheathing on the exterior of the wire.All NM cable within 8’ from the ground should be provided physical protection.
It should be in conduit or some other sort of enclosure that provides physical protection from 18" below the surface of the ground to 8' above the surface of the ground.
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