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<p>Interesting but scary subject for me ! I hope we don't find out
how well they work !<br>
</p>
<p><br>
</p>
<p>The MidNite SPDs use MOVs with a rating of 15 nano-second
response time.</p>
<p>This response time is in line for type 2 and 3 EMP events but
your mileage may vary.</p>
<p>Type 1 EMPs (pico-seconds ?) have faster rise and fall times so
will fall outside those specifications but</p>
<p>might help ? I don't know. Up here in the pacific northwest,
Boeing actually has an</p>
<p>EMP test facility for military aircraft and equipment... It is
very expensive to book</p>
<p>time there I am told by my brother Robin, who has submitted
equipment to in a past</p>
<p>life and work-place.<br>
</p>
<p><br>
</p>
<p>EMPs are kind of like lightning in that the field strength will
vary depending on</p>
<p>distance from and strength of the source as well as how much the
wires connecting your</p>
<p>equipment to the outside world act as antennas.... Like a
lightning strike, results may just be <br>
</p>
<p>luck of the draw, especially if it were to be like a direct hit
and short rise/fall times.<br>
</p>
<p><br>
</p>
<p>I would guess that wire length (resonance) may have a effect on
how well they act as an antenna for</p>
<p>a given pulse width for lightning or an EMP ?</p>
<p><br>
</p>
<p>Faraday cages may not help at all unless they are used for
storing spare equipment and with NO wires</p>
<p>exiting and entering. Ferrites connected as common mode
filtering (all wires passing through) may <br>
</p>
<p>or may not help on external wiring either.</p>
<p><br>
</p>
<p>If an EMP does occur, I would replace the SPDs with new ones to
be safe for the next one... <br>
</p>
<p>And do not hesitate to give us a call and tell us how well it
worked ! You might need to leave</p>
<p>a message though as we will probably be very busy at that time.<br>
</p>
<p><br>
</p>
<p>boB, at SPI in Vegas</p>
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 9/9/2017 4:22 PM,
<a class="moz-txt-link-abbreviated" href="mailto:drake.chamberlin@redwoodalliance.org">drake.chamberlin@redwoodalliance.org</a> wrote:<br>
</div>
<blockquote type="cite"
cite="mid:702fdc95b105cd6b4c25d51524369acedf60b944@webmail.redwoodalliance.org">How
about using a solid metal enclosure instead of a mesh? Would that
cover frequency differences?<br>
<br>
One thing railroad tracks and telegraph wires have in common is
that they are very long metallic conductors. The charged particles
cut across the conductors for extended distances, That situation
would be similar with a grid connected inverter. <br>
<br>
If the inverter were isolated from the grid, with the breakers
turned off (or removed), maybe that would help, depending on the
magnitude of the pulse. <br>
<br>
The electronics would need to be isolated from the grounded,
conductive cover of the enclosure. The equipment should be
isolated by design with neutral and ground separate. <br>
<br>
Would a Midnite surge protector be of any help in an EMP event? <br>
<br>
Thanks,<br>
<br>
Drake <br>
<br>
<br>
<br>
<blockquote class="atmailquote"><br>
----- Original Message -----<br>
<div id="origionalMessageFromField"
style="width:100%;display:inline;background:rgb(228,228,228);">
<div style="display:inline;font-weight:bold;">From:</div>
"RE-wrenches" <a class="moz-txt-link-rfc2396E" href="mailto:re-wrenches@lists.re-wrenches.org"><re-wrenches@lists.re-wrenches.org></a></div>
<br>
<div id="origionalMessageToField"
style="display:inline;font-weight:bold;">To:</div>
"RE-wrenches" <a class="moz-txt-link-rfc2396E" href="mailto:re-wrenches@lists.re-wrenches.org"><re-wrenches@lists.re-wrenches.org></a><br>
<div id="origionalMessageSentField"
style="display:inline;font-weight:bold;">Cc:</div>
<br>
<div style="display:inline;font-weight:bold;">Sent:</div>
Fri, 8 Sep 2017 14:56:37 -0400<br>
<div id="origionalMessageSubjectField"
style="display:inline;font-weight:bold;">Subject:</div>
Re: [RE-wrenches] EMP - Faraday Cages<br>
<br>
<br>
<div>Spent a little time over the last few years trying to study
this, there is dozens of answers to the same question it seems
if you surround it with mesh it depends on the spaces size in
the mesh and it also depends on the frequency of the EMP</div>
<div><br>
</div>
<div>I would not bet that just putting a disconnect in the wires
would help but lightning is capable of jumping miles across
the sky I can't imagine that an emp would be any different I'm
sure it could bridge a gap the size of a breaker or disconnect
relatively easily.</div>
<div><br>
</div>
<div>During the Carrington event in the 1800s it was setting
railroad ties on fire as well as burning down telegraph
offices</div>
<div><br>
</div>
<div>I'm afraid the best bet would be a back up inverter and
controller properly wrapped and shielded and make the sign of
the cross and pray for the best !</div>
<div><br>
</div>
<div>And if it's atmospheric like a solar pulse or other
challenge you would want to wait several days before you
brought out your back up stuff because you may get hit again
in a matter of hours or days and it be a shame to get
everything possibly working again and have it wiped out by the
2nd hit</div>
<div><br>
</div>
<div>I'm probably already outside of what Michael would like me
to be so we can continue later if you like</div>
<div><br>
</div>
<div>Bob ellison</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
On Sep 8, 2017, at 12:22 PM, <a
href="mailto:drake.chamberlin@redwoodalliance.org"
moz-do-not-send="true">drake.chamberlin@redwoodalliance.org</a>
wrote:<br>
<br>
</div>
<blockquote>
<div>In 2013 we were having a discussion of Faraday cages. I
don't think we ever got an answer to the question of whether
a grounded inverter or charge control enclosure would serve
as a Faraday cage? If all external lines were disconnected,
would the grounded metal enclosure prevent damage from an
EMP?<br>
<br>
Thanks,<br>
<br>
Drake<br>
<br>
<p class="darkgray font13">
<span class="sender pipe"><a
href="https://www.mail-archive.com/search?l=re-wrenches@lists.re-wrenches.org&q=from:%22Chris+Daum%22"
moz-do-not-send="true"><span><span>Chris Daum</span></span></a></span>
<span class="date"><a
href="https://www.mail-archive.com/search?l=re-wrenches@lists.re-wrenches.org&q=date:20130507"
moz-do-not-send="true">Tue, 07 May 2013 12:21:16 -0700</a></span>
</p>
<pre>Dear people:
So I have a customer worried about the end of the world as we know it. I've
looked at the HP archives and see comments from a while ago. Other than
screening/boxing components and adding mucho surge protectors, is there
anything else that can be done that might actually work?
Thanks!
Chris Daum
Oasis Montana Inc</pre>
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