# How basic can a faraday cage be?



## icantthinkofausername (Feb 7, 2014)

I made a very simple one to store a small solar array and some electronics out of an old popcorn tin then wraped the electronics in some drawstring backpacks. Is this enough?

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## LincTex (Apr 1, 2011)

What exactly is "an old popcorn tin"? Like an aluminum foil pie pan?

I oftentimes wonder if a solar array or solar panel needs to be protected. I have a hard time picturing how it could get damaged by an EMP.


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## Caribou (Aug 18, 2012)

Yes, an old popcorn tin is fine. You have insulated the electronics from the metal so you should be fine. To test put a cell phone in with the other stuff and call it, if it rings you need to work on your system.


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## GrinnanBarrett (Aug 31, 2012)

You can use a metal trash can and line it with something like cardboard. Be sure the bottom, sides and top inside the lid are insulated from contact with the electronics. 

You also can look at bags like the ones they use to send home a toll tag in before you put it on your windshield. It appears to be not much more than a Mylar bag sealed up in reality it is a plastic bag or pouch that has been impregnated with metal.

A "Booster" bag or shopping bag lined with aluminum foil will also work really well. You can ask shoplifters who use them to avoid tag detection when stealing items that go through a scanner as you leave the store. 

Do a search on Google or yahoo or Wiki and see what may come up. Good luck. GB


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## Geek999 (Jul 9, 2013)

If you're not confident, layered faraday cages are supposed to help, so consider placing the popcorn tin inside a slightly larger can. Each layer adds to the protection.


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## Caribou (Aug 18, 2012)

I put a spare set of electronics for my boiler in old cookie tins. The cardboard box that the spare parts come in is a great insulator and I just put the lid on the tin and place it on top of the boiler till I need the parts. Not only are they protected but if the boiler goes out in the middle of the night I am prepared with all the parts I might need.


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## LincTex (Apr 1, 2011)

Caribou said:


> I put a spare set of electronics for my boiler in old cookie tins. The cardboard box that the spare parts come in is a great insulator and I just put the lid on the tin ...


Do one better.... make a layer of aluminum tape around the lid, sealing it.


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## Beaniemaster2 (May 22, 2012)

Any solid metal container will work as long as it metal hits metal at all times... Cardboard is a great liner yes and every item in the cage must not touch the sides or each other... Larger cages such as a wire one to put generators in must be grounded for a proper discharge... An old unplugged microwave makes a very good Faraday cage... So do Army ammo cans... 

My hubby has a Defibulator so we are planning to build one that he can sit it if a CME is coming... Won't help for a EMP cause you wouldn't have any notice to get in it... Just hoping for the best if that happens...


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## labotomi (Feb 14, 2010)

Beaniemaster2 said:


> My hubby has a Defibulator so we are planning to build one that he can sit it if a CME is coming... Won't help for a EMP cause you wouldn't have any notice to get in it... Just hoping for the best if that happens...


A faraday cage is not useful for the effects of a CME. The good news is that his defibrillator won't be affected by a CME


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## Beaniemaster2 (May 22, 2012)

labotomi said:


> A faraday cage is not useful for the effects of a CME. The good news is that his defibrillator won't be affected by a CME


I'm surprised nobody commented on your post.... With all the evidence out there, just how did you come to this conclusion??????


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## LincTex (Apr 1, 2011)

Beaniemaster2 said:


> I'm surprised nobody commented on your post.... With all the evidence out there, just how did you come to this conclusion??????


Familiarity with various wavelengths, as well as the intensity and the stages of the event.

CME kills long telegraph and power lines because they act as huge antennae. If you are plugged into the circuits on these lines the risk of damage is high. Unplug your stuff and you should be fine.

The intensity of a HEMP event is such that per square meter of surface area, the voltages induced are very high. Too much voltage is what fries the semiconductors.


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## labotomi (Feb 14, 2010)

Beaniemaster2 said:


> I'm surprised nobody commented on your post.... With all the evidence out there, just how did you come to this conclusion??????


What LincTex said.

Here's a little more explanation.

An EMP has three distinct components (events) occurring in succession... E1, E2 and E3.

The E1 component caused damage to electronics because of how fast the voltage rises. You can have one end of a wire at thousands of volts higher than the other end. A faraday cage can protect it's contents from this.

The E3 component is due to the movement of the Earths Magnetic field. Any magnetic field that moves across a conductor induces voltage into that conductor. That voltage may be small with short conductors but will increase with the length. A CME moves the Earths Magnetic field, so it is like the E3 component of an EMP. A faraday cage does nothing toward protection from this.


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## LincTex (Apr 1, 2011)

Back to the top again


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## crabapple (Jan 1, 2012)

I first heard of a Faraday cage on this forum.
Two posters went back & forth on the need for a grounded cage.
Anyways, I know a little now.
Will storing the electronics in a underground building help at all.
Or will the EMP / CME past though 5-10 feet of soil & 12 inches of concrete.


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## Marcus (May 13, 2012)

Crabapple,
The ground will protect all of your electronics by dissipating the charge from the electrons. A CME or E3 only affects long runs of conductors like power lines, or anything plugged into power outlets.


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## sillybilly (Sep 18, 2014)

So, a question: i have some goalzero batteries that the company recommends keeping them plugged in 24/7 and that's ok for those. I am building a wooden box and lining it with several rolls I bought of copper mesh. I can put all my solar panels and electronics in it but what about our GZ batts that need to be plugged in?


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## Jim1590 (Jul 11, 2012)

I know nothing about the topic on hand, but reading the posts from linc and labotomi, I would imagine that the mere fact your batterys are plugged into the grid to maintain the levels makes the faraday cage useless. Any event strong enough to fry things will cause disruption along the line. 

Maybe build your box but have solar panels for a trickle charger on the box itself? Again, I am clueless on this, just typing what makes sense to me.


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## cowboyhermit (Nov 10, 2012)

Yup, like Jim1590 says, anything plugged into the grid is at risk to some degree. Disconnected, actual batteries are essentially immune to any sort of real world EMP, however some newer batteries (Li-ion) that have additional circuitry could theoretically be damaged. Solar panels themselves are also on the extremely unlikely to be effected side of things, simply due to their nature.


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## LincTex (Apr 1, 2011)

sillybilly said:


> So, a question: I have some goalzero batteries ....what about our GZ batts?


How are they made?

Are they SLA? Are they AGM? Lithium-Ion?


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