# EMP power? **URL:** \ **Category:** Factual Questions\ **Created:** [February 16, 2023, 7:24pm UTC](https://boards.straightdope.com/t/emp-power/979908 "2023-02-16T19:24:51Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Sitnam](https://avatars.discourse-cdn.com/v4/letter/s/6a8cbe/32.png) [@Sitnam](https://boards.straightdope.com/u/Sitnam)\ **Post date:** [February 16, 2023, 7:24pm UTC](https://boards.straightdope.com/t/emp-power/979908/1 "2023-02-16T19:24:51Z")
[Starfish Prime](https://en.wikipedia.org/wiki/Starfish_Prime) was a atmospheric nuclear test done in the Pacific during the 60’s. It’s EMP yield was far larger than expected and it alone was estimated to be able to have wiped out all the electronics in the lower United States if it was detonated miles above Kansas. “A 1.4 Megaton bomb launched about 250 miles above Kansas would destroy most of the electronics that were not protected in the entire Continental United States. During the brief return to atmospheric testing in 1962, a 1.4 megaton nuclear weapon was detonated over Johnston Island at an altitude of about 250 miles. The effects of EMP were observed in Hawaii, 800 miles east of the detonation. Streetlights and fuses failed on Oahu and telephone service was disrupted on the Island of Kauai” [HERE](https://doh.wa.gov/sites/default/files/legacy/Documents/Pubs/320-090_elecpuls_fs.pdf) 1.4 is not a lot, that’s ridiculously small in fact. Tsar Bomba, the largest ever detonated, was in the 50-58 range. Can a 1.4 Megaton nuclear weapon detonated over Kansas really wipeout all the electronics in the lower 48? I just don’t believe we are that susceptible to EMP attack. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 16, 2023, 7:35pm UTC](https://boards.straightdope.com/t/emp-power/979908/2 "2023-02-16T19:35:21Z")
Here are some previous threads on the general idea of EMP attacks. They’re sorted from most recent to oldest. Note most of these are pretty old and should probably not be posted into now: > [@A few questions about nuclear EMP](https://boards.straightdope.com/t/a-few-questions-about-nuclear-emp/838689): > > In the wake of a nuclear EMP attack, what sort of equipment would be needed to get power grids and electricity back up and running again? What do the repairs involve? Is it possible for a nuclear weapon to emit very little EMP? When a nuclear weapon causes radar blackout (makes radar coverage in the vicinity useless for several minutes,) is that EMP itself at work, or some other physics/magnetism thing? > [@Electromagnetic pulse attack question?](https://boards.straightdope.com/t/electromagnetic-pulse-attack-question/810879): > > Would a submarine survive an EMP strike if it was submerged? Peter Vincent Pry — executive director of the task force on National and Homeland Security > [@Electromagnetic pulse and technology](https://boards.straightdope.com/t/electromagnetic-pulse-and-technology/739257): > > I just picked up a book (which I haven’t started reading yet) about a world where an Electromagnetic Pulse wipes out all technology which is dependent on electronics, and, according to the book cover “plunges civilization into a new dark age.” So, I have to ask, how much of “technology” can survive an EMP? Are there cars still being manufactured which don’t rely on electronics? How far back do we have to go to find cars that would still run? What about motorcycles? What about infrastructure… > [@Using Nuclear Weapons' Compton Effect as EMP](https://boards.straightdope.com/t/using-nuclear-weapons-compton-effect-as-emp/338385): > > In one game which I shall not name, the evil guys have a plan to detonate a nuclear weapon above a city to initiate a compton effect, which, IIRC, were supposed to act like an EMP device, basically destroying all of the electronics within the city. Would this really work without completely wiping the city from the map, or coating it in layers of radioactive fallout? > [@Question about Electromagnetic Pulses (EMP)](https://boards.straightdope.com/t/question-about-electromagnetic-pulses-emp/293765): > > An EMP will destroy any electronic device, like computers, within its blast radius, but it will not destoy electical devices like flashlights. At least that is my understanding. My questions are: What ‘piece’ is it that electronic devices have that electrical devices don’t that an EMP breaks and why does the EMP break it. > [@of nuclear and EMP](https://boards.straightdope.com/t/of-nuclear-and-emp/243613): > > Basic question: Why would a nuclear explosion creat a wave or “EMP’” -Regards > [@Electromagnetic pulses](https://boards.straightdope.com/t/electromagnetic-pulses/157801): > > Last week in my high school history class, we watched the made-for-TV movie “The Day After,” detailing the effects of nuclear war. In that movie, I heard the term “electromagnetic pulse” to describe a nuke’s ability to cut off all power at and around Ground Zero. My history teacher told us that this would cause cars to stop, planes to fall from the sky, etcetera, FOREVER. My question is, the pulse isn’t a tangible thing, so where does it go that makes all electronics stop functioning for all … ---
**Author:** ![scudsucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scudsucker/32/14101_2.png) [@scudsucker](https://boards.straightdope.com/u/scudsucker)\ **Post date:** [February 16, 2023, 7:53pm UTC](https://boards.straightdope.com/t/emp-power/979908/3 "2023-02-16T19:53:40Z")
Not to be to be too facetious; but it appears that, at least, the Texas grid could be taken down by the EMP from a firecracker ETA : Probably too soon for facetious answers, my apologies to OP and the mods. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [February 17, 2023, 3:35am UTC](https://boards.straightdope.com/t/emp-power/979908/4 "2023-02-17T03:35:55Z")
The warning about EMP is that it will destroy electronics, since modern chips are very sensitive to over-voltage. However, I note that the effects described for Hawaii appear to rely on the power grid - i.e. extremely long leads for the pulse, and for house to house wiring, very long and straight. I wonder if network wiring (ethernet) would be vulnerable to the same, and if so, how long a lead cable would make the electronics at risk. Would wifi antennas have a similar vulnerability? the foot or less of trace on a computer circuit board? Machines boxed up for sale and not connected? Would those surge protectors power bars make a difference? The Air Force apparently has a facility for testing EMP - a giant trestle bridge, all wood with no nails or other metal construction, is how I’ve seen it described. Someone must have done the tests and be able to give a good estimate of what level of computer destruction we could see… ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [February 17, 2023, 1:16pm UTC](https://boards.straightdope.com/t/emp-power/979908/5 "2023-02-17T13:16:44Z")
> [@md-2000](#): > > The Air Force apparently has a facility for testing EMP - a giant trestle bridge, all wood with no nails or other metal construction, is how I’ve seen it described. The one at Kirtland? Was just there in December. Drove around the structure, but didn’t walk around it. It’s big. A person we were with told us it is the biggest wood structure ever built. Anyway, the subject of EMP (and in particular E1 HEMP) is a big and complex subject. The [Wiki page](https://en.wikipedia.org/wiki/Nuclear_electromagnetic_pulse) on it is quite informative. And [this paper](https://web.archive.org/web/20170520145500/https://www.ferc.gov/industries/electric/indus-act/reliability/cybersecurity/ferc_meta-r-320.pdf) is an excellent intro to the subject. Suffice to say, there are a lot of variables in play when it comes to the vulnerability of an electronics system to EMP. ---
**Author:** ![Hypno-Toad](https://avatars.discourse-cdn.com/v4/letter/h/b2d939/32.png) [@Hypno-Toad](https://boards.straightdope.com/u/Hypno-Toad)\ **Post date:** [February 17, 2023, 1:31pm UTC](https://boards.straightdope.com/t/emp-power/979908/6 "2023-02-17T13:31:07Z")
Would a Faraday Cage provide protection from an EMP? ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [February 17, 2023, 1:48pm UTC](https://boards.straightdope.com/t/emp-power/979908/7 "2023-02-17T13:48:32Z")
Depends on a number of variables. For the cage itself, the primary variables are the conductivity of the material, the thickness of the material (skin effect issues), and area & geometry of any apertures or openings. The latter is usually the biggest problem; for the vast majority of systems, there still needs to be a way to get power and signals (often including visible light) into and out of the system. And that’s for “regular” EM fields. A standard faraday cage won’t block static & low frequency magnetic fields, and thus won’t block static & low frequency magnetic interference. A compass, for example, will work perfectly fine inside a standard faraday cage. If you wanna redirect static & low frequency magnetic fields, you need to also enclose the system with a material that has high magnetic permeability. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [February 17, 2023, 5:55pm UTC](https://boards.straightdope.com/t/emp-power/979908/8 "2023-02-17T17:55:04Z")
> [@Crafter\_Man](#): > > > [@md-2000](#): > > > > The Air Force apparently has a facility for testing EMP - a giant trestle bridge, all wood with no nails or other metal construction, is how I’ve seen it described. > > The one at Kirtland? Was just there in December. Drove around the structure, but didn’t walk around it. It’s big. A person we were with told us it is the biggest wood structure ever built. See here for the Kirtland EMP test facility: > **[ATLAS-I](https://en.wikipedia.org/wiki/ATLAS-I)** > > ATLAS-I (Air Force Weapons Lab Transmission-Line Aircraft Simulator), better known as Trestle, was a unique electromagnetic pulse (EMP) generation and testing apparatus built between 1972 and 1980 during the Cold War at Sandia National Laboratories near Kirtland Air Force Base in Albuquerque, New Mexico. > ATLAS-I was the largest NNEMP (non-nuclear electromagnetic pulse) generator in the world, designed to test the radiation hardening of strategic aircraft systems against EMP pulses from nuclear w... According to Google Map’s current imagery it’s still there and apparently intact, although ref the wiki, there’s no way for us to tell if it’s somewhere between structurally unreliable and falling apart. https://maps.google.com/maps?ll=35.0301364,-106.5592561&z=17&output=embed&dg=ntvb&q=ATLAS-I