Electrical Engineering - solid detonator leg wires? solid circuit wires? why?

Author

solid detonator leg wires? solid circuit wires? why?

chemstu

2006-05-17, 11:21 pm

Does anyone know why commercial detonators have small gage solid
conductor leg wires? And why only solid conductor wire is recommended
in a blast circuit?

I have an idea, but I cannot be sure. I have some electrical/physics
knowledge, and I understand that both solid wire and stranded wire have
advantages, but I do not understand the details as to the why solid
wires are chosen in commercial caps. There is so much unreliable info
on the web about comparisons between solid and stranded wire -
especially as it pertains to the home audio and data communication
industries. Some of the info is contradictory. It is hard to sift
through it all.

Here is what I know on the subject: The DC current carrying capacity
between solid and stranded wire is negligible in most cases.

I understand that skin effect allows higher frequency AC to travel
easier through stranded wire than it does through solid wire because of
the increased surface area due to multiple strands. Although, at least
a high frequencies, I believe that the benefit gained from skin effect
is in turn lessened by the slight inductances that can set up between
individual strands. Then there is the matter of corrosion throughout a
stranded wire on the surface the strands or between strands that grows
with time. No doubt these inductances etc. degrade signals - I am
assuming that that is the main reason that CAT5/6 is solid conductor.
It seems that stranded wire is only advised for CAT 5/6 when patching
and where physical stress is expected on the wire.

I am aware that DC voltage is used to fire a detonator. However, at
least in case of an EBW, foil, etc., the current pulse rise times are
so fast that, the waveform appears as critical as the current and
voltage delivered. High frequency? at least for one pulse?

Then there is the notion of physical durability of wire. In cases of
physical usage, stranded wire outperforms solid sire due to its
flexibility. However a detonator is not a repeated use item.

I am sure that stranded wire will work in a blast circuit in the real
world. There are plenty of sites for homebrew detonators that instruct
the maker to use stranded wire. But, I am specifically speaking of the
sole use solid wire in commercial caps. I have read that article about
the failure of the IED that Ted K made and tried to use. Apparently an
EOD investigator concluded that had he used solid wire the IED would
have detonated. So, solid wire appears critical doesn't it.

Theories -

Stranded wire - reasons to use:
1. flexibility?
2. skin effect allows for faster rise time in detonation pulse?

Solid conductor wire - reasons to use
1. inflexible, possibly wires assist in physically holding the
detonator in place?
2. inflexible, leg wires are not expected to be bent many times
3. lack of skin effect not benefit not a problem - likely true with
slower caps
4. lack of skin effect not benefit not a problem - waveform not
critical affected for EBW etc..
5. broken wire can be discovered easier than with stranded before use
6. less possibility of corrosion buildup as between strands in stranded
wire
7. less possibility of inducing current into stranded wire broken
strands from ext RF source
8. more reliable connection when wires are twisted?

I hope I am not to far off in my theories. Please feel free to comment
on my theories and to any specific relevance to an explanation as to
why solid wire is chosen in commercial detonators. Any other info is
appreciated.

THX, EC

**THE-RFI-EMI-GUY**

2006-05-19, 2:21 am

I am guessing 4 and 5, but on McGuiver, #1 (for solid) always helps with
the C4.

Whenever I watch a crime show where they are disarming a bomb, I wonder
two things:

1) Why isn't there a standardized color code convention, the bomb squad
is left there to guess red or blue, very inefficient.
2) Why not just nip the wire right at the detonator and be done for the
day?

Does anybody remember the extortion bombing at Harrahs where the "Xerox
Repairman" left the juggernaut bomb with all the toggle switches?

chemstu wrote:

>Does anyone know why commercial detonators have small gage solid
>conductor leg wires? And why only solid conductor wire is recommended
>in a blast circuit?
>
>I have an idea, but I cannot be sure. I have some electrical/physics
>knowledge, and I understand that both solid wire and stranded wire have
>advantages, but I do not understand the details as to the why solid
>wires are chosen in commercial caps. There is so much unreliable info
>on the web about comparisons between solid and stranded wire -
>especially as it pertains to the home audio and data communication
>industries. Some of the info is contradictory. It is hard to sift
>through it all.
>
>Here is what I know on the subject: The DC current carrying capacity
>between solid and stranded wire is negligible in most cases.
>
>I understand that skin effect allows higher frequency AC to travel
>easier through stranded wire than it does through solid wire because of
>the increased surface area due to multiple strands. Although, at least
>a high frequencies, I believe that the benefit gained from skin effect
>is in turn lessened by the slight inductances that can set up between
>individual strands. Then there is the matter of corrosion throughout a
>stranded wire on the surface the strands or between strands that grows
>with time. No doubt these inductances etc. degrade signals - I am
>assuming that that is the main reason that CAT5/6 is solid conductor.
>It seems that stranded wire is only advised for CAT 5/6 when patching
>and where physical stress is expected on the wire.
>
>I am aware that DC voltage is used to fire a detonator. However, at
>least in case of an EBW, foil, etc., the current pulse rise times are
>so fast that, the waveform appears as critical as the current and
>voltage delivered. High frequency? at least for one pulse?
>
>Then there is the notion of physical durability of wire. In cases of
>physical usage, stranded wire outperforms solid sire due to its
>flexibility. However a detonator is not a repeated use item.
>
>I am sure that stranded wire will work in a blast circuit in the real
>world. There are plenty of sites for homebrew detonators that instruct
>the maker to use stranded wire. But, I am specifically speaking of the
>sole use solid wire in commercial caps. I have read that article about
>the failure of the IED that Ted K made and tried to use. Apparently an
>EOD investigator concluded that had he used solid wire the IED would
>have detonated. So, solid wire appears critical doesn't it.
>
>Theories -
>
>Stranded wire - reasons to use:
>1. flexibility?
>2. skin effect allows for faster rise time in detonation pulse?
>
>Solid conductor wire - reasons to use
>1. inflexible, possibly wires assist in physically holding the
>detonator in place?
>2. inflexible, leg wires are not expected to be bent many times
>3. lack of skin effect not benefit not a problem - likely true with
>slower caps
>4. lack of skin effect not benefit not a problem - waveform not
>critical affected for EBW etc..
>5. broken wire can be discovered easier than with stranded before use
>6. less possibility of corrosion buildup as between strands in stranded
>wire
>7. less possibility of inducing current into stranded wire broken
>strands from ext RF source
>8. more reliable connection when wires are twisted?
>
>I hope I am not to far off in my theories. Please feel free to comment
>on my theories and to any specific relevance to an explanation as to
>why solid wire is chosen in commercial detonators. Any other info is
>appreciated.
>
>THX, EC
>
>
>

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"©

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

Paul Hovnanian P.E.

2006-05-19, 2:21 am

chemstu wrote:
>
> Does anyone know why commercial detonators have small gage solid
> conductor leg wires? And why only solid conductor wire is recommended
> in a blast circuit?

Good question. I've seen detonators inserted into dynamite and, IIRC,
they shove the detonator in by pushing on the wires. Its easier to push
on stiff, solid wire than flexible stranded stuff.

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
One World, One Web, One Program - Microsoft Promotional Ad
Ein Volk, Ein Reich, Ein Fuhrer - Adolf Hitler

Paul Hovnanian P.E.

2006-05-19, 3:21 am

**THE-RFI-EMI-GUY** wrote:
>
> I am guessing 4 and 5, but on McGuiver, #1 (for solid) always helps with
> the C4.
>
> Whenever I watch a crime show where they are disarming a bomb, I wonder
> two things:
>
> 1) Why isn't there a standardized color code convention, the bomb squad
> is left there to guess red or blue, very inefficient.

I guess the terrorists would have to agree on whether to follow the ANSI
or IEC color codes.
I suppose they could check with the AHJ for the appropriate codes. But
then you know how lax those inspectors are getting lately.

;-)

--
Paul Hovnanian mailto:Paul@Hovnanian.com
------------------------------------------------------------------
On a clear disk, you can seek forever.

chemstu

2006-05-19, 6:21 am

Well, thanks for the ideas everyone, I am sure everyone can see that
there are different ideas out there - I posted this question with a
couple of other engineering/physics groups - same result.

I am thinking that the idea of the lack of integrity/reliability of the
individual strands in stranded wire, which could result in insufficient
current carrying ability and might not allow detonators to function
properly, seems like a good answer as far as the functioning of the
wires. I also see the logic in the other ideas about ease of handling.

However, as you can read on the web, various states i.e. PA, NJ etc.
not only require by law that detonators have solid leg wires - but
that all wiring in the blast circuit be solid conductor also.

This leads me to again see the logic of the idea the physical integrity
of the wiring - which in turn relates to the integrity current
capacity - is seen as critical enough to induce both, the manufacturers
to assemble detonators with solid wires, and individual states to pass
laws requiring that solid wiring be used for detonators and detonator
circuits.

PS I am glad for the replies and that a couple of people
actually found the question intriguing, I at first thought that no-one
would reply.

THX EC

spamTHISbrp@yahoo.com

2006-05-19, 2:21 pm

**THE-RFI-EMI-GUY** wrote:
> 2) Why not just nip the wire right at the detonator and be done for the
> day?

> --
> Joe Leikhim K4SAT
> "The RFI-EMI-GUY"=A9
>
> "Treason doth never prosper: what's the reason?
> For if it prosper, none dare call it treason."
>
> "Follow The Money" ;-P

I imagine a sophisticated device will have multiple detonators, with a
small current running through each, and a current sensor.

Current in any detonator drops, *boom*

Dave

hob

2006-05-19, 2:21 pm

"chemstu" <explosivechemistry@hotmail.com> wrote in message
news:1148027571.771013.87000@j55g2000cwa.googlegroups.com...
> Well, thanks for the ideas everyone, I am sure everyone can see that
> there are different ideas out there - I posted this question with a
> couple of other engineering/physics groups - same result.
>
> I am thinking that the idea of the lack of integrity/reliability of the
> individual strands in stranded wire, which could result in insufficient
> current carrying ability and might not allow detonators to function
> properly, seems like a good answer as far as the functioning of the
> wires. I also see the logic in the other ideas about ease of handling.

In short - not insufficient carrying capacity -
rather, 1 stray wire from a stranded wire connection, either intact or
broken off and laying across a gap, either as a conductor or arc source,
make things go boom when they are not supposed to.

fwiw....

>
> However, as you can read on the web, various states i.e. PA, NJ etc.
> not only require by law that detonators have solid leg wires - but
> that all wiring in the blast circuit be solid conductor also.
>
> This leads me to again see the logic of the idea the physical integrity
> of the wiring - which in turn relates to the integrity current
> capacity - is seen as critical enough to induce both, the manufacturers
> to assemble detonators with solid wires, and individual states to pass
> laws requiring that solid wiring be used for detonators and detonator
> circuits.
>
> PS I am glad for the replies and that a couple of people
> actually found the question intriguing, I at first thought that no-one
> would reply.
>
> THX EC
>

Spokesman

2006-05-19, 6:21 pm

"chemstu" <explosivechemistry@hotmail.com> wrote in message
news:1147915374.484556.214920@j73g2000cwa.googlegroups.com...
> Does anyone know why commercial detonators have small gage solid
> conductor leg wires? And why only solid conductor wire is recommended
> in a blast circuit?
>
> I have an idea, but I cannot be sure. I have some electrical/physics
> knowledge, and I understand that both solid wire and stranded wire have
> advantages, but I do not understand the details as to the why solid
> wires are chosen in commercial caps. There is so much unreliable info
> on the web about comparisons between solid and stranded wire -
> especially as it pertains to the home audio and data communication
> industries. Some of the info is contradictory. It is hard to sift
> through it all.
>
> Here is what I know on the subject: The DC current carrying capacity
> between solid and stranded wire is negligible in most cases.
>
> I understand that skin effect allows higher frequency AC to travel
> easier through stranded wire than it does through solid wire because of
> the increased surface area due to multiple strands. Although, at least
> a high frequencies, I believe that the benefit gained from skin effect
> is in turn lessened by the slight inductances that can set up between
> individual strands. Then there is the matter of corrosion throughout a
> stranded wire on the surface the strands or between strands that grows
> with time. No doubt these inductances etc. degrade signals - I am
> assuming that that is the main reason that CAT5/6 is solid conductor.
> It seems that stranded wire is only advised for CAT 5/6 when patching
> and where physical stress is expected on the wire.
>
> I am aware that DC voltage is used to fire a detonator. However, at
> least in case of an EBW, foil, etc., the current pulse rise times are
> so fast that, the waveform appears as critical as the current and
> voltage delivered. High frequency? at least for one pulse?
>
> Then there is the notion of physical durability of wire. In cases of
> physical usage, stranded wire outperforms solid sire due to its
> flexibility. However a detonator is not a repeated use item.
>
> I am sure that stranded wire will work in a blast circuit in the real
> world. There are plenty of sites for homebrew detonators that instruct
> the maker to use stranded wire. But, I am specifically speaking of the
> sole use solid wire in commercial caps. I have read that article about
> the failure of the IED that Ted K made and tried to use. Apparently an
> EOD investigator concluded that had he used solid wire the IED would
> have detonated. So, solid wire appears critical doesn't it.
>
> Theories -
>
> Stranded wire - reasons to use:
> 1. flexibility?
> 2. skin effect allows for faster rise time in detonation pulse?
>
> Solid conductor wire - reasons to use
> 1. inflexible, possibly wires assist in physically holding the
> detonator in place?
> 2. inflexible, leg wires are not expected to be bent many times
> 3. lack of skin effect not benefit not a problem - likely true with
> slower caps
> 4. lack of skin effect not benefit not a problem - waveform not
> critical affected for EBW etc..
> 5. broken wire can be discovered easier than with stranded before use
> 6. less possibility of corrosion buildup as between strands in stranded
> wire
> 7. less possibility of inducing current into stranded wire broken
> strands from ext RF source
> 8. more reliable connection when wires are twisted?
>
> I hope I am not to far off in my theories. Please feel free to comment
> on my theories and to any specific relevance to an explanation as to
> why solid wire is chosen in commercial detonators. Any other info is
> appreciated.
>
> THX, EC
>

daestrom

2006-05-19, 6:21 pm

Roy L. Fuchs

2006-05-20, 5:21 pm

On 17 May 2006 18:22:54 -0700, "chemstu"
<explosivechemistry@hotmail.com> Gave us:

>I understand that skin effect allows higher frequency AC to travel
>easier through stranded wire than it does through solid wire because of
>the increased surface area due to multiple strands.

Not true. Unless they are individually insulated from each other
along their length, they become integrated together, and skin effect
is nullified as the wire is seen as one larger conductor from a field
propagation POV.

IF they were individually insulated from each other along their
length, you would have the beginnings of a Litz Wire configuration, or
at least would be able to see some of the effects you refer to and
that true Litz Wires sport.

Roy L. Fuchs

2006-05-20, 5:21 pm

On 17 May 2006 18:22:54 -0700, "chemstu"
<explosivechemistry@hotmail.com> Gave us:

> I believe that the benefit gained from skin effect
>is in turn lessened by the slight inductances that can set up between
>individual strands.

You should go back and study your electronics.

Roy L. Fuchs

2006-05-20, 5:21 pm

On 17 May 2006 18:22:54 -0700, "chemstu"
<explosivechemistry@hotmail.com> Gave us:

> Then there is the matter of corrosion throughout a
>stranded wire on the surface the strands or between strands that grows
>with time. No doubt these inductances etc. degrade signals - I am
>assuming that that is the main reason that CAT5/6 is solid conductor.

Nope. Also, insulated conductors do not corrode (at least not the
way you make it sound). That is the whole point of the insulations
aside from keeping them from touching each other making undesired
conduction paths.

Roy L. Fuchs

2006-05-20, 5:21 pm

On 17 May 2006 18:22:54 -0700, "chemstu"
<explosivechemistry@hotmail.com> Gave us:

>It seems that stranded wire is only advised for CAT 5/6 when patching
>and where physical stress is expected on the wire.

Now you are starting to get yourself a clue.

Stranded wires can flex hundreds of times with no damage to the
conductors.

Solid wire can only be flexed a couple of times before wire damage
begins.

The reason is that copper "work hardens". That means when you take a
solid wire (or bar) of copper, and bend it, the micro-crystalline
structure of the media in the region in and around the bend "work
hardens". Then, when you bend it back, you create small tears in that
micro-crystalline structure and the process of wire breakage begins.

This occurs when the bends are sharp, and fast and forced on the
copper. In a stranded wire setting, the bend is managed better and
has a much reduced net damage on the wire as a whole as well as less
on any individual strand in the bundle.

Roy L. Fuchs

2006-05-20, 5:21 pm

On Thu, 18 May 2006 22:19:28 -0700, "Paul Hovnanian P.E."
<Paul@Hovnanian.com> Gave us:

>chemstu wrote:
>
>Good question. I've seen detonators inserted into dynamite and, IIRC,
>they shove the detonator in by pushing on the wires. Its easier to push
>on stiff, solid wire than flexible stranded stuff.

Shove it in... shove it in... --TV commercial

Roy L. Fuchs

2006-05-20, 5:21 pm

On 19 May 2006 09:49:57 -0700, spamTHISbrp@yahoo.com Gave us:

>
>**THE-RFI-EMI-GUY** wrote:
>
>
>I imagine a sophisticated device will have multiple detonators, with a
>small current running through each, and a current sensor.
>
>Current in any detonator drops, *boom*
>
Yes. There is never full knowledge as to whether there is a
redundant or not either. If there is one sitting out, exposed, it
could even be a dummy (likely too).

WITH a current sense on it... again... BOOM!

Bada Big Boom!

Line Monster

2006-05-25, 6:21 am

Date: Thu, May 18, 2006, 10:24pm (EDT-3) From: Paul@Hovnanian.com
(Paul=A0Hovnanian=A0P.E.)
**THE-RFI-EMI-GUY** wrote:

I am guessing 4 and 5, but on McGuiver, #1 (for solid) always helps with
the C4.
Whenever I watch a crime show where they are disarming a bomb, I wonder
two things:
1) Why isn't there a standardized color code convention, the bomb squad
is left there to guess red or blue, very inefficient.

I guess the terrorists would have to agree on whether to follow the ANSI
or IEC color codes.
I suppose they could check with the AHJ for the appropriate codes. But
then you know how lax those inspectors are getting lately.
;-)
--
Paul Hovnanian =A0 =A0 mailto:Paul@Hovnanian.com
----------------------------------------------
On a clear disk, you can seek forever.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>

Good One Paul ;-)

I was wondering as well ~ Why on Earth if a Terrorist wants to blow
something up with no regard to Life what so ever; Why would coding his
Bomb device matter to him at all ? Most likely he will use any available
Telephone Bell Wire he steals from the Hotel or House he's hiding out
in;If he buys it it'll be most likely a single color roll all
around....Unless he wants to show off his craftyness and that costs more
;-) not a Big Issue with Blowing up Stuff.

On the other hand, it seems to me in those Bomb Squad Capers that the
Detonators are Shielded from eyesight and usually protected with a trip
circuit or other component from just Pulling Out the wire Solutions ~
the Explosive material or Detonator are usually not accesible in TV ~
why would they be different in Real Life Cases, any smart bomber would
try and trick any Bomb Tech into triggering his or her device employing
the obvious wire scheme approach... Like in McGyver cutting a sinlgle
wire with a nailclipper may not work well & KaBoom !

However, In Commercial Applications:
It is Wise and Prudent and Beyond Lawful to Follow The Codes in the
event One as the Assembler might be called off to another site leaving
the device to Chance Knowhow, Rather than as a Uniform [predictable]
Serviceable Product...

Now Freezing The Device seems to work giving them some extra time to
handle the Dastradly Gadgets in TV Land.

Kumano Eats Wires like Candy
McGruffffff

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