[Olam]

Yes this is a very timley subject, from what I have read so far, a faraday cage would not be sufficient. Whoever is planning to do this has thought of that.
Also from what I have read sofar, you would have to put the protected equipment at least 3-5 feet in the ground and have it stored in metal boxes, also inside the box, sheild the stuff with aluminium paper.

So basically, the strenght of the attack would such that it might be wise to have backup "electronics" or communicating equipment that uses tube technology..ie...old stuff that is pre-transistor and ic chip tech.

For cars, you need old deisel engines that are not governed by electronics and injection systems.

I have been looking at old transiever ham radios on ebay that work with tubes. Its just difficult to know if they really work as most sellers mention that they don't guarantee on having them functional.