I would say the biggest risk to most people (that are not directly under the blast) is what the power lines will pick up and carry into your home via outlets. The power lines are antennas and there will be huge surges. One thing that is very effective at preventing that is to place NTC thermistors rated for just above line level after breakers and fuses. When a voltage spike comes in, they become short circuits and absorb the energy (usually destroying themselves) while the same pops the fuse or breaker disconnecting the device. We had lightning hit a power line and smoke a marine battery charger. One replacement thermistor and fuse and the charger was fine.
That EMP shield device you have there must do something similar??
That EMP shield device you have there must do something similar??