Lightning-like flashes from exploding electrical transformers punctuated the night, often followed by the wail of emergency vehicles' sirens.

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PCBs were routinely used until about 25 years ago in the manufacture of a number of items, including electrical transformers.

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Main.net has found that even in the noisiest electrical environments, such as neighborhood transformers, there are always big enough gaps in the radio spectrum for repeaters to push a signal through.

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The answer is clear to space physicists and electrical engineers: it would blow out transformers and melt down our computer systems.

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Should some of the roughly 300 transformers that are the backbone of our electrical grid be damaged or destroyed, the interruption to the electrical grid will not be brief.

CENTERFORSECURITYPOLICY: EMP and you

Any electrical or electronic device - including the grid's transformers - not shielded against this pulse would be, at best, taken temporarily off-line.

CENTERFORSECURITYPOLICY: EMP and you