Will Your Electronic Safe Open After An EMP? How to Protect Your Gear

EMP - Safe

Did you know that if you own a safe with an electronic lock that you might be locked-out of it after an EMP? And that’s not exactly good timing. That’s right folks! Depending on who made the safe, its model, where the safe is located, and the distance away from the EMP source, you may or may not be able to access the goodies that you have tucked away in that fancy electronic safe!

A good friend of mine who is trying to be as prepared as possible called me the other day and asked me about his electronic safe and how it would handle a possible EMP. Jerry is a smart guy so when he had this question, I figured there may be others out there wrestling with this same question, so I decided to address this question as well as adding the additional advice I provided to my friend about protecting his supplies and gear…

Let’s start by looking at what one manufacturer has said about their electronic safe. I found this email response to a consumer’s question about Barrett safes and their ability to withstand an electromagnetic pulse (EMP)… here is the reply that was on the company forum:

“Thank you for your inquiry. Currently our electronic locks are not EMP rated or tested. If the lock were to fail electronically, a safe technician would still be able to open the lock by penetrating the door and lock casing to move the bolt. If there is concern regarding the accessibility of safe contents following an EMP situation, it would be recommended that a mechanical lock be used in this case.

Scott Hicks
Sargent & Greenleaf, Inc. Help Desk”

So, from the terms ‘not EMP rated or tested’ I think we can assume the answer is that; their safe is not EMP-proof. And ‘they’ recommend safes with mechanical locks for EMP situations. OK, so we see there is some potential vulnerability at least with the electronic safes at one major company. And it’s probably reasonable to assume that may be the case with many other companies, and their safes may also be vulnerable to EMP, unless they will warrantee the safe as being EMP hardened.

So how does an EMP damage the integrated circuits like the ones inside your cell phones, computers, car & truck ignition systems, and dozens of other everyday items, including that fancy electronic safe?  That was also part of Jerry’s question, and the full answer is by its nature highly technical. Of course this is an excellent question, and it’s the kind of question that more people need to be asking!

Disaster preparedness planning is not a one-size fits-all paradigm… there are many variables, and the trick is to solve as many potential problems with the best planning and the least amount of equipment and related costs.

Proper planning requires a clear understanding of the challenges!

EMP - integrated circuit

An integrated circuit

So how does an EMP damage the integrated circuits in your electronics?

Integrated circuits like the one pictured above have a very specific operating voltage. The operating voltages of integrated circuits is very low, and can range from just over one-volt to 5-volts D.C. (direct current). Most people understand that if they were to accidentally connect an appliance to the wrong voltage, it would severely damage the appliance or device. Nonetheless, to prevent a device from being powered by the wrong type (AC current versus DC current) or amount of voltage, manufacturers use a specific plug on appliance cords that use 120-VAC, and totally a different plug on 240-VAC appliances; it prevents mistakes. In the case of battery-operated devices, they accomplish the same thing by the plugs and the size of the compartment for the particular battery required. The bottom line is that devices are very sensitive to applying the wrong type or amount of electrical current.

When a nuclear weapon is discharged in the upper atmosphere it generates a very potent electromagnetic pulse of energy, which can affect a very large geographical area (thousands of square miles). This is also known as a ‘high-altitude electromagnetic pulse’ (HEMP).  As I mentioned before, the EMP phenomenon is technical, and certainly well beyond the scope of this article, but for those are would like a power-point explanation of it, you can go here: http://williamesimpson.com/hemp-iemi-and-severe-geomagnetic-storm-effects-on-critical-infrastructures


The bottom line for people and devices located on the surface of the planet below the HEMP discharge and downrange in all directions for a thousand miles or more, is that a huge transitory electromagnetic field is generated at the surface of the planet. This electromagnetic field is of sufficient strength to cause high-voltage to flow in any conductors (wires, circuits, etc.). What happens when you move a copper wire through a magnetic field? The answer is; it causes electrical current to flow in that wire, and this is essentially how a generator works (spinning a coil of wire in a magnetic field).  So when a massive electromagnetic pulse hits your unprotected (un-shielded) devices, it does the same thing, but the voltage that is developed from the EMP field in devices greatly exceeds the operating voltages of the circuits, so they get cooked (no, they don’t catch on fire; the damage is internal). So what can you do?

The big problem with an EMP attack (or a localized EMP caused by a lightning strike) is there is virtually no warning; there is no time to get anything done. Either you are ready, or you’re not, and then you suffer the consequences. It’s not like you’ll have time to shove everything you want to keep functioning into a Faraday Cage, which is basically a metal box or ‘cage’ that attenuates the field strength of the EMP. Attenuation (the reduction of the EMP field strength) is an important concept here, since many people don’t have a perfect Faraday Cage that is large enough to protect all their gear.

So why would we have so little warning ahead of an EMP attack? Well, this short video discusses an example of one such scenario and provides some insight as to why there is little or no warning:


So as we see from the video, arguably, with a near-coastal launch of an EMP weapon taking as little as 60 seconds, and with the speed of a ballistic missile, the military might have as much as 15 minutes warning! Civilians would have much less than that, if any, before all the electronics over a very large area are toast.

OK, so now what? Are there any solutions for everyday people? Absolutely!

Let’s start with the simplest, least expensive solution and work our way up to the biggest and arguably the best solution for average Preppers.


EMP - types of safe locks

If you’re considering a safe, look at the old-school dial combination (mechanical) lock, as opposed to an electronically locked safe, which by the way, uses a battery.

If you already own an electronic safe, I have a possible solution and an option for you a bit further down…

Faraday Cage Protection:

 EMP - all metal garbage can

All-metal garbage can becomes an effective Faraday Cage with a mod.

Metal garbage cans are ubiquitous and can be bought at most hardware stores fairly inexpensively. The metal can should be lined with an electrical insulator such as cardboard (you don’t want anything stored inside touching the metal can) and then packed with anything you want to protect. The metal lid should fit snugly with a metal-to-metal fit and as seen in the photo above. The lid can be securely held in place with a bungee cord. The obvious disadvantages are limited space and dealing with placing square boxes in a cylinder.

EMP - all metal cargo trailer

A new all-metal cargo trailer can become an effective Faraday Cage

Small cargo trailers (used) can be purchased fairly reasonably. I have seen many such trailers selling used for about $1,000.00. All-metal cargo trailers can also be used effectively as Faraday Cage storage, if the trailer is truly ‘all-metal’ (the roofs on some trailers have plastic vent covers, which must be replaced, or properly shielded (covered with metal foil). It is also best to connect an earth-ground to the trailer. This is accomplished by going to your local building supply and buying a grounding spike (designed to ground a household electrical system) and an appropriate length of #6 or larger copper wire, which is securely connected to the ground spike (which is driven deeply into the earth… see local electrical code for depth) and then to the frame of the trailer. When you connect the ground wire to the trailer, use a copper lug that is soldered to the copper wire and bolt the lug to clean bare metal on the trailer frame. The connections should then be coated with epoxy or a quality corrosion-blocking compound.

EMP - shipping container

Steel, ocean-going shipping containers are top-drawer solutions for Preppers

The military and other well-financed public and private companies can afford to have consulting firms design and build buildings and structures that are ‘shielded’ from EMP. Most people cannot afford that, but might be able to afford a used shipping container. These robust steel containers are very solidly built; onboard container ships they will regularly stack them 8-10 high on top of each other. And keep in mind, they aren’t empty! Prices vary depending on where you are in the country and the age and condition of the container. On the West Coast, I have seen ‘used’ 40-foot containers for as little as $2,800.00. Of course you will also have to pay to have it delivered to where it will be used.

EMP - shipping container in seaShipping containers can be securely locked-up with their existing locking mechanisms, and they are waterproof unless they have been damaged or are rusted-through, which takes decades near the sea. If you are considering a container, make sure to walk the roof of the container; if there is any damage (deformed metal, large dents, holes) find another one. Be very wary of containers with recent repairs; there’s nothing worse than a leaky container!

EMP - shipping container insulation

Cardboard from large appliance boxes is great to insulate the inside

It’s important to keep anything that is stored in the container from touching the metal of the container, if you’re using it for EMP protection. You can use steel storage racks, etc. inside the container as long as they don’t touch the metal container anywhere. The heavy cardboard from large appliance boxes is perfect as an electrical insulator for lining the inside of a shipping container as needed.

And if you’re one of the people who unfortunately bought a safe with an electronic lock, then you can place the safe inside the container (of course it too must be insulated and must not touch the metal of the container anywhere). Note: Those owners of electronic safes might alternatively have a safe-tech come-out and retro-fit the safe with a mechanical lock (may cost a couple hundred dollars or more).

EMP - shipping container copper grounding

Solid copper grounding wire secured to the container

I like to secure copper ground wires to all four corners of the container as an extra precaution. While it’s true that if the shipping container is setting on moist earth it is likely well-grounded as a result of the extensive surface area of the container sitting on the ground, I still prefer to add the grounding as outlined herein above.

So as we see, there are EMP solutions at almost every level of affordability depending on the size of space required.

Being prepared today, means being ready for tomorrow!

Cheers! Capt. Bill

Capt. William E. Simpson II - USMM Ret.
Semper Veritas / Semper Paratus

IMDb: http://www.imdb.com/name/nm6505899/
Twitter:  https://twitter.com/NauticalPrepper
Member:  Authors Guild

About the Author:


Capt. William E. Simpson II is a U.S. Merchant Marine Officer with decades of boating and expedition sailing experience, having logged more than 150,000 miles at sea. Capt. Simpson has successfully survived long-term ‘off the grid’ at sea and at remote uninhabited desert islands with his family ...


DIY, Tips & Tricks, Emergency Power, Emergency Preparedness, Most Popular, Prepping, Recent Articles, Self Reliance


shipping container, EMP solution, emp, emergency power

3 thoughts on “Will Your Electronic Safe Open After An EMP? How to Protect Your Gear”

  • Curious

    What modification(s) if any would be required to protect the electronic equipment from a CME?


    • Capt. William E. Simpson


      In order to answer your question in a meaningful way, we first need to review some basics.
      A Coronal Mass Ejection ('CME') is a burst of plasma (charged particles) from the sun. Understanding what effects it will have on electronic devices on earth requires that we understand a bit of physics and electromagnetic theory; when a conductor moves relative to a magnetic field, electrons (current) flows in the conductor, which is known as ‘electromagnetic induction’.

      The plasma cloud that is emitted by the sun during a CME has tremendous mass. Even though it is not a 'solid' mass, its total mass is so immense that it generates its own magnetic field. The strength and orientation (polarity) of the plasma cloud's magnetic field is an important consideration when considering its effect on the earth. Basically, the crust of the earth contains a considerable amount of conductive minerals such as iron. So when the magnetic field moves past the earth’s crust, it generates current (flow of electrons). The amount of current that is generated in the crust of the earth when a plasma cloud from a CME passes depends upon several factors, including but not limited to; the size of the magnetic field, the strength and polarity (orientation) of the magnetic field of the cloud relative to the earth's magnetic field and the localization of conductive minerals in the earth's crust (some geographic areas of the earth's crust contain more conductive minerals). As the cloud's magnetic field passes, the power that can flow in the earth’s crust at the surface can easily be sufficient to generate huge voltage spikes in many conductors. Power lines and any other long wires can develop huge transient voltages as the magnetic field passes (even after the grid fails), which can damage many electrical devices that are attached to these conductors. Some long-wire antennas for instance, metal antenna towers (cell towers) can also become electromagnetic inductors, and could therefore discharge damaging current into any associated radio equipment that might be attached. As things stand today, any such massive voltage fluctuations, such as seen during the Carrington Event of 1859, would certainly permanently take-down the national energy grid, but not before hammering most everything that it touches. Therefore, even if you have a generator and fuel, anything that was plugged-in during the event, would likely be toast.

      In a Carrington-sized event (which is not as big as they can come), certainly, anything that is plugged into the electrical grid, or that is attached to any long wire or conductor as the plasma cloud's magnetic field passes the earth could be irreversibly damaged.

      That said, stand-alone devices (not attached to the grid) that contain solid-state components, transistors and integrated circuits such as those in your car and in your electronically locked safe would be unaffected by the magnetic field generated by a CME.

      I hope this response if helpful for your planning needs.

      Cheers! Capt. Bill

      Capt. William E. Simpson II - USMM Ret.
      Semper Veritas / Semper Paratus

      IMDb: http://www.imdb.com/name/nm6505899/
      Twitter: https://twitter.com/NauticalPrepper

  • James E. Satterthwaite

    Hello Capt. Bill,

    Thank you for writing this valuable piece.

    With an Electronic Safe, might I have a prayer if I...?:
    1. Place the Electronic Keypad in a Faraday Cage
    2. Place metal tape over the entire keypad receiver to shield and make continuity of the safe outer shell
    3. Attach a Ground the Safe's Outer Shell

    Thanks for your consideration!!!

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