A question was asked in the WTF thread about microwave oven shielding being sufficient against EMP. Consensus seems to be "no" because of the holes and seams allowing stronger RF in.

So, what can you do?

Delliottg posted this in another prepping thread:

https://www.askaprepper.com/10-faraday- ... e-at-home/

Seems the big thing is to completely encase the thing to be protected. Metal (copper) tape the closure, isolate the item inside from touching the box, and grounding the exterior (so you don't end up being the thing which discharges it.)

Wa State Department of Health Office of Radiation Protection has this to say:

"WHAT CAN BE DONE TO PROTECT ELECTRONICS
There are two basic ways to protect or harden items against EMP effects. The first
method is metallic shielding. Shields are made of a continuous piece of metal such as
steel or copper. A metal enclosure generally does not fully shield the interior because of
the small holes that are likely to exist. Therefore, this type of shielding often contains
additional elements to create the barrier. Commonly, only a fraction of a millimeter of a
metal is needed to supply adequate protection. This shield must completely surround
the item to be hardened.
The second method, tailored hardening, is a more cost-effective way of hardening. In
this method, only the most vulnerable elements and circuits are redesigned to be more
rugged. The more rugged elements will be able to withstand much higher currents. This
method has shown unpredictable failures in testing, though it is thought it may be useful
to make existing systems less vulnerable."

https://doh.wa.gov/sites/default/files/ ... uls_fs.pdf