A conductive enclosure, done carefully, attenuates the fast part of a pulse. People use it for radios, drives, and spare electronics: nested containers, clean seams, no accidental antenna poking through as a charging cable. Test it with a phone and a known signal before you trust it with the only radio you own.

Attenuate means weaken. A conductive shell gives the fast field somewhere to run that is not the circuit inside. Seams, holes, and a cable left plugged through the wall are where that fails, because the cable is an antenna the box invited in. Nested containers are an admission that one layer will be imperfect. None of this touches the slow current on a transmission line.

That project is worth an afternoon. It is not a substitute for grid policy. E3 current in a 500-kilovolt line does not care about the ammo can in your closet. Both scales are real; mixing them up produces either false comfort or fatalism.

A phone and a known signal are a crude test, which is why they are worth doing before you trust the box with the only radio. If the phone still hears the signal, the enclosure is not finished. If the phone goes quiet, you have learned something and you have still not certified the box against a pulse. Put a spare through the drill. Do not put the grid’s recovery in the same container.

If you shield one thing, shield the thing that tells you what happened and the thing that lights the room after. Everything else is optional.

The ammo can and the 500-kilovolt line are both real and they are not substitutes. False comfort is treating the afternoon project as if it had hardened the bulk system. Fatalism is deciding that, because the line is unprotected, the radio and the light do not matter either. You can do the household scale while insisting the other scale is someone else’s unfinished job.

If only two things fit, make them the thing that tells you what happened and the thing that lights the room after. A dead drive full of saved articles does not brief you. A light you can actually turn on keeps the room usable enough to read the paper plan. The rest of a gadget drawer is optional, and it can stay optional without apology.