Slow Breakdown - How will you be hit?

[Steve]

Here's a good article on Faraday Cages:

http://www.futurescience.com/emp/emp-grounding.html

"Remember that a faraday cage without any wire penetrations does not need to be grounded, and any attempt to ground such an uncomplicated faraday cage is simply asking for problems."

My own Faraday cage is the "multi layer" approach. A metal shipping container containing metal filing cabinets and an 800kg metal safe, none of it is grounded, each layer sits on wood. I have electricity wired in, for lights and equipment, but the metal cabinets and safe should provide protection for their contents from unexpected EMP, and if an event looked likely I would remove the connection completely.