[backwoods-engineer]

It is theoretically IMPOSSIBLE for any electromagnetic impulse to pass through any conductive barrier, even the metallic screen wire on the old “screen door”.

No. Go back to microwave engineering class.

The intensity on the far side of a cutoff waveguide is proportional to the inverse-square of the distance where the intensity is measured. Depending on the frequencies that make it up, and its intensity, EMP will cause some problems with screened electronics.

But that ain't the main problem.

The main problem is the so-called E3 pulse, the long-wavelength geomagnetic currents that are induced in the earth and in long electric wires. Those are powerful enough to burn out gigawatt power turbines. Ask the Russians about that one.

[Huebolt]

Thanks to all for the info. I had to go without electricity for 29 hours due to storm damage and agree it is back to the stone age.

12 v.d.c. LED systems for backup seem ok for light, but all those other appliances are, as you say, goners.

It is a real problem that lead acid storage batteries are both expensive and short-lived. Static inverters are not bad.