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I was my understanding that when using a Faraday wrap for your electronics (tube or SS), that it should NOT be grounded or touch ground, as that's a way in for the pulse and defeats the purpose of the wrap.

Is that correct or incorrect?

Well, the ham folklore says either to wrap it in aluminum foil or bury it, so I was suggesting a belt-and-suspenders approach ≤]B^)

In thinking about it, there are tradeoffs to protect against an EMP. The Faraday cage (aluminum foil and so forth) certainly would work against an EMP in its electromagnetic wave form, provided that it was really well sealed (no gaps).

Undoubtedly, an EMP creates high ground currents, but the question is how deeply they penetrate. Since the EMP is a very short-duration pulse, there will be a significant skin effect at and near the surface of the ground, causing a falloff of current density with increasing depth. Howver, ground is in most places a poor conductor, so the depth at which the currents are negligible might be deeoer than you would want to bury something.

The conductive enclosure would still, in my opinion, be useful to shunt the ground currents around its contents; but it's possible that the density of those currents in contact with the shield could be large enough to burn through it if it was very thin.

This completes my guesswork package of the evening.