When using ENT, what is recommended for protecting against penetration by screws or nails in wood?

Using a steel plate or bushing is recommended for protecting against penetration by screws or nails in wood when using electrical non-metallic tubing (ENT). The primary purpose of this protection is to prevent damage to the ENT and the wires contained within it. In applications where wood or other structural materials may be subjected to significant mechanical penetration, placing a steel plate or bushing ensures that the ENT remains intact and prevents exposure to sharp objects that could compromise the electrical safety of the installation.

Steel plates or bushings are particularly effective because they are durable and can withstand higher levels of force compared to other materials. This is crucial in environments where wood framing might be fastened together using screws, nails, or other fasteners, as these could easily puncture the ENT without adequate protection.

The other options may not provide the same level of protection or may not be suited for use with ENT, which makes them less appropriate choices.