I'm betting most of the stuff in my shop (not attached to the grid) will be just fine, even in the case of a nuke induced EMP.
/johnny
If you'd like for your metal building to serve as a Faraday Cage/screen room, make sure that the metal roof and doors are electrically bonded together and then run ground straps from the building's lower sides to grounding stakes driven into the ground. That would likely save all electrical equipment in the building and, if you have an electrical generator, would probably spare that as well. You'll probably be depending on the generator for quite some time until the electrical grid is restored - a year or two maybe??
It bears reading the recent book “One Second After” to get a well defined picture of how any modern society will fair in such an event regardless of the source of the EMP event.
1986 Ontario/Quebec power grid failure and US 1858?? events where fence wire was hot-to-touch/burned the posts and large sections of telegraph system was destroyed illustrates what happens from a “small” scale EMP.
If the area the event effects is multi-country/continent then the recovery time will be long and filled with many dead people - whole sections of a society are venerable to the effects. Cars built after 1972 (Chrysler introduced electronic ignition in 1973, Ford & GMC later) will be dead and not coming back to life without a complete system replacement. Some automotive batteries and deepcycle batteries with photovoltaic units (they will be toast) will cook-off and land line telephones will go down.
Planet-wide societies today are so dependent on electrical/electronic devices that ANY replacement equipment will not be available for 9+months or years.
Therein is the main reason to have a society-wide effort to build in some safety-factors now.