Creating a transcontinental powergrid might take time

... and is not necessary.

A HEMP might give you something like a dozen kilovolts per meter, so what. Yes, this will fry integrated circuits because anything that has something that can act as an antenna which is more than a few centimeters long will grab several hundred volts from the pulse. CPUs and SDRAM don't like that kind of stuff happening.

It is unclear whether such a thing would even affect a hoover, a mixer, or an electric drilling machine other than possibly destroying a few circuits in the power supply unit. They're made to withstand 240V indefinitely, so they'll withstand 500-800V for 0.1 seconds, too (well, possibly).

But in no case will this affect overland powerlines. A power line that is built for a regular 380kV shouldn't have much trouble with an extra 500kV for 0.1 seconds. Yes, the computers in the control center will be fried, but "the transcontinental grid", no way.

Yes, the physical infrastructure, poles, cables, etc, would remain mostly unharmed. You might lose some lengths here and there due to pole fires, and there would be lots of work to rebuild much of the substation equipment, but restoring the electrical grid after an EMP event would actually be far easier than the 1998 ice storms that hit the North East.

A lot of the generation capacity would be hindered, but I have yet to see a non-nuclear power plant that the local engineers could not reconfigure and have most systems rebuilt in a few weeks time. (They wouldn't have all the safeties, they would require more staff to monitor, and in many cases would be far less efficient, but unless something actually took out the boilers somehow, then you can convert the site with relative ease.) Recovering would be easier than you might think as we would most likely ration power and greatly reduce demand while things were restored over time.

Major city centres would be an exceptional risk, especially in the USA. If they get a few idiots whipping people up and doing the general fear-mongering thing before leadership can step up and get the population under control then things will go badly. If local level leadership can keep people calm and from panicking, then it really wouldn't be terrible.

Yes, the physical infrastructure, poles, cables, etc, would remain mostly unharmed. You might lose some lengths here and there due to pole fires, and there would be lots of work to rebuild much of the substation equipment, but restoring the electrical grid after an EMP event would actually be far easier than the 1998 ice storms that hit the North East.

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Wouldn't an EMP blow out every transformer on the line ?

Yes, the physical infrastructure, poles, cables, etc, would remain mostly unharmed. You might lose some lengths here and there due to pole fires, and there would be lots of work to rebuild much of the substation equipment, but restoring the electrical grid after an EMP event would actually be far easier than the 1998 ice storms that hit the North East.

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Wouldn't an EMP blow out every transformer on the line ?

Probably would pop most of them in active use, but every utility has lots and warehouses full of spares, and they're not exactly hard to replace. What delayed fixing the grid after the storms was the amount of work it took to actually get to any of the lines, and how many lines and towers had to actually be replaced, which is far harder than only replacing the pole-top hardware.

In cases like that the plan would normally be to restore power to central cores and primary services, and work out from there.

A USB port is connected to a controller card ... If some one detonated a nuke in the ionosphere, it would *FRY* everything in an area roughly the landmass of the US.

No it wouldn't. This is a popular misconception brought about by Sci-Fi and Hollywood. Some devices controllers might fry some radios and TVs would suffer interference there may be some power surges that would kill some equipment but, the chances are that in the most cases it would be a slight annoyance and not armageddon. Cars would continue working, power stations would continue working. Nuclear reactors are shielded anyway.

If there was a blast big enough to take out every electrical device in the US then guess what... it wouldn't matter because every single person would have been killed by the blast no matter how high up in the Ionosphere it was.

EMP weapons were something that the US flirted with in the cold war but but found they would have no effect because all the Russian electrical equipment was too well insulated as standard when compared with US components.

No it wouldn't. This is a popular misconception brought about by Sci-Fi and Hollywood.

USB should have current-limiting resistors right after the metal bit on the outside which prevent that kind of thing from the cable side, much like an USB connector is not susceptible to static discharge. After all, end-users touch USB plugs all day long. If every discharge killed a device, it would be catastrophical.

However, I could very well imagine that it looks much different for computer components. A standard DIMM is 82 millimeters long, so it must have a circuit at least 82mm long. Let's say 100mm because almost certainly it's not possible to make all circuits as short as the theoretical minimum.

That's a nice little 0.1m long antenna. Given a 10kV/m pulse, you'll have 1,000V over these 0.1m, on a circuit that is used to see 1.5V. Surely that isn't precisely healthy.

No it wouldn't. This is a popular misconception brought about by Sci-Fi and Hollywood.

USB should have current-limiting resistors right after the metal bit on the outside which prevent that kind of thing from the cable side, much like an USB connector is not susceptible to static discharge. After all, end-users touch USB plugs all day long. If every discharge killed a device, it would be catastrophical.

However, I could very well imagine that it looks much different for computer components. A standard DIMM is 82 millimeters long, so it must have a circuit at least 82mm long. Let's say 100mm because almost certainly it's not possible to make all circuits as short as the theoretical minimum.

That's a nice little 0.1m long antenna. Given a 10kV/m pulse, you'll have 1,000V over these 0.1m, on a circuit that is used to see 1.5V. Surely that isn't precisely healthy.

Except that the DIMM is inside a metal box (the computer case) which is inside a building with steel reinforcements and there are other metalic structures nearby cars, phone boxes, street lamps, lighting conductors and it is one of millions of buildings in the US. Now I'm not saying your DIMM would not get damaged just that some will and some won't.

Probably would pop most of them in active use, but every utility has lots and warehouses full of spares, and they're not exactly hard to replace. What delayed fixing the grid after the storms was the amount of work it took to actually get to any of the lines, and how many lines and towers had to actually be replaced, which is far harder than only replacing the pole-top hardware.

In cases like that the plan would normally be to restore power to central cores and primary services, and work out from there.

While that is true for a smaller scale where power starts getting repaired in a matter of hours, if the damage is bad enough it will be a few days before the "central core" pieces get back online, and that is where things fall apart.

As long as power to enough areas get restored quickly enough then they can serve to restart other areas. Service vehicles can refuel, and power can get rerouted to critical infrastructure to bootstrap other systems.

But if the damage is severe enough that no station is able to restore power to nearby areas quickly enough, then reserve fuel becomes scarce. It becomes difficult to find fuel to transport the equipment from the warehouse to the field. That is the nightmare scenario.

Consider that "sufficiently large" solar event is vague. It doesn't happen often, but they can be so large that moons and even planetary orbits are destabilized. We would have a little warning, but for a sufficiently large ejection, really all you could announce is that roughly half the planet is about to be destroyed. A smaller event that is documented as happening every few centuries could likely severely damage most of the electrical infrastructure of every region it hits, as well as knocking satellites from the sky. Those, simply, would be bad.

Yes, pumping fuel without power is such a problem. If only we had some sort of device that a human could use without electricity to move liquids... Some kind of "Hand pump", like the ones I've seen kicking around in pretty much every electrical utility service garage I've ever been to. Now, I've only been to a few such garages, and only in Atlantic Canada, but I would be really surprised to know that they're randomly uniquely seen in my part of the world, given how dead simple they are to build.

Some kind of "Hand pump", like the ones I've seen kicking around in pretty much every electrical utility service garage I've ever been to.

Pft, a few places I've been in America people are too lazy to fill their own cars, never mind use a hand pump. Self service was uncommon at mom'n'pop gas stations.

It may be different north of the border in canuck land, and here in the UK it's worse than that, many of the petrol stations are unmanned or only manned part of the day, and you need to put a credit card in the pump to vend fuel. If you came up against one of those with no electricity you'd be well and truly screwed, time for a plan B, as in "bilking".

You'd find that lots of unscrupulous looters would be stealing your gas with a hose pipe and some ingenuity rather than try and hand pump it out of the reservoir of the gas station...