ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

ECN Shout Chat
Top Posters(30 Days)
Admin 19
Recent Posts
NFPA stuff
by gfretwell. 03/28/17 08:08 PM
Anyone hiring inspectors?
by HotLine1. 03/27/17 08:03 AM
Old decora style outlets
by Admin. 03/25/17 11:40 AM
ESA Arc flash course
by TheShockDoctors. 03/24/17 10:15 AM
fuse rejectors
by HotLine1. 03/24/17 07:53 AM
New in the Gallery:
SE cable question
Popular Topics(Views)
231,684 Are you busy
166,592 Re: Forum
160,767 Need opinion
Who's Online Now
0 registered members (), 64 guests, and 10 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#45519 - 12/01/04 02:41 PM How do you protect against EMP?  
SolarPowered  Offline
Member
Joined: Jul 2004
Posts: 625
Palo Alto, CA, USA
The current thread about radios causing havoc with GFCIs and other electrical equipment got me to wondering about something.

There is currently talk that there is a very real danger of terrorists using a nuclear device in this country, either in the immediate future, or in the longer term. Nuclear detonations generate an "EMP" (electromagnetic pulse) that can destroy unprotected electronic equipment for at least hundreds, if not thousands, of miles outside the blast area.

How do you go about protecting equipment from EMP? I've heard that it can be done, but I've never seen anything at all about how to go about actually doing it.

It seems like this is really important to do in any sort of emergency facility, like hospitals and emergency control centers. It's clearly of extreme importance that the radios of emergency responders continue to operate after a nuclear "event." The same applies to the huge amount of medical electronics that ambulances and hospitals rely on to keep people alive.

[This message has been edited by SolarPowered (edited 12-01-2004).]


Work Gear for Electricians and the Trades

#45520 - 12/01/04 02:52 PM Re: How do you protect against EMP?  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Here is a link that has some info along with more links.

http://www.unitedstatesaction.com/emp_and_faraday_cages.htm

That one is a little technical I like the layman's version.

http://zapatopi.net/afdb.html

They say it is for protection against mind control but it should help against EMP. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#45521 - 12/01/04 03:04 PM Re: How do you protect against EMP?  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
If you are not familiar with EMP here is a basic explanation of it along with more links.

http://science.howstuffworks.com/e-bomb.htm/printable


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#45522 - 12/01/04 08:01 PM Re: How do you protect against EMP?  
hbiss  Offline
Member
Joined: Dec 2003
Posts: 886
Hawthorne, NY USA
Dunno. If protection is as simple as wrapping a piece of equipment with foil or some other conductive material and grounding it, wouldn't the steel enclosure used on most computers and other equipment do the same thing? It should be grounded through the line cord.

I really have little knowledge in this area and I always assumed there was little hope for non-military equipment in the event of EMP exposure.

-Hal


#45523 - 12/01/04 09:15 PM Re: How do you protect against EMP?  
resqcapt19  Offline
Member
Joined: Nov 2000
Posts: 2,148
IL
Look at this Air Force document on EMP protection for buidlings . Note it is a large PDF file.
Don


Don(resqcapt19)

#45524 - 12/01/04 11:49 PM Re: How do you protect against EMP?  
hbiss  Offline
Member
Joined: Dec 2003
Posts: 886
Hawthorne, NY USA
That document relates to TEMPEST which I very vaguely remember something about. It's a RF shielding system designed to keep "spies" from evesdropping via RF leakage from computer and other equipment.

The only mention of EMP is where the document states that the system [TEMPEST]contrasts with high altitude EMP (HEMP) shielding which protects against nuclear electromagnetic effect infiltration into sensitive electronic equipment.

It's also 14 years old.

-Hal


#45525 - 12/02/04 12:59 PM Re: How do you protect against EMP?  
vars  Offline
Junior Member
Joined: Oct 2003
Posts: 6
NJ
Something very interesting about an EMP is that silicon IC devices (transistors) are much more succeptable to failure from an EMP than the good old vacuum tube.

The avionics in a soviet MIG-25, a modern jet fighter make heavy use of vacuum tubes. One theory is that this is to harden the machine to EMP caused by nuclear fallout. You can read more about this and other EMP hardening techniques here:
http://www.globalsecurity.org/wmd/library/report/1984/ERD.htm

So keep that all american-5 Philco radio up and running in case of emergency!!

-vars


#45526 - 12/02/04 06:02 PM Re: How do you protect against EMP?  
hbiss  Offline
Member
Joined: Dec 2003
Posts: 886
Hawthorne, NY USA
You can fire up your "All American 5" but what are you going to listen to? Broadcasting stations went solid state long ago also.

-Hal


#45527 - 12/02/04 06:14 PM Re: How do you protect against EMP?  
hbiss  Offline
Member
Joined: Dec 2003
Posts: 886
Hawthorne, NY USA
On topic- I remember about a year ago that law enforcement was testing a device to stop fleeing cars and put an end to high speed chases. With one method, the fleeing car would be followed and a skateboard type antenna would be fired by explosive charge so as to go under the car. Tethered by a cable to the chase vehicle, a strong EMP would then be directed at the car which would disable the engine computer as well as the ignition system and other electronics.

Kill their 2000 watt sound system and they will be dead in the water. [Linked Image]

-Hal


#45528 - 12/02/04 10:22 PM Re: How do you protect against EMP?  
dereckbc  Offline
Member
Joined: Oct 2003
Posts: 156
Tulsa, OK
I worked with EMP shielding for the military while I was at MCI. Most of the pratical know-how info is classified. For the most part it is shielding the equipment building and equipment in a metal mesh or sheet plating, and multi-ground the shield to earth for a building, or skin of an aircraft. Any conductors power and signal that enter have a TVSS device on steroids installed in a specified location where they can be integrated into the building sheild. Some of the concepts are discussed in the sites mentioned earlier, but the most of the specs are classified.

[This message has been edited by dereckbc (edited 12-02-2004).]



Member Spotlight
The_Lightman
The_Lightman
Orlando, Fl, USA
Posts: 49
Joined: August 2001
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.020s Queries: 14 (0.003s) Memory: 0.8088 MB (Peak: 0.9812 MB) Zlib enabled. Server Time: 2017-03-29 05:12:21 UTC