Re: High voltage leads from coax

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Brett Miller <brmtesla2-at-yahoo-dot-com> 

Ed,

Yeah, I have some RG-213 left over from a recent HF
antenna installation that I'm thinking about using at
least the sheild.  It's wonderfull stuff, especially
suited for ground connections.

-Brett


--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > Original poster: Ed Phillips <evp-at-pacbell-dot-net>
 >
 > A couple of things to consider:
 >
 > 1. Polyethylene insulation is flammable; be
 > carereful!.  I remember
 > vividly seeing a movie of a big building-mounted
 > radar system (FPS-85?)
 > on fire.  Had a large number of traveling wave tube
 > amplifiers taking DC
 > from a giant power supply.  Somehow (no one could
 > ever tell how) one of
 > the coax (must have been big stuff!) DC leads arced
 > and caught fire,
 > setting the whole building full of coax on fire.
 > Once the outer braid
 > got hot enough the insulation just melted and
 > dripped out and fed the
 > fire until it burned itself out.  As I recall this
 > was at Eglin AFB and
 > for some reason the fire department couldn'g get to
 > the building.  An
 > interesting point was that the movie accompanied a
 > lecture on the FPS-85
 > (?).  When we walked into the meeting room the
 > moving was playing along
 > in the background and no one paid any attention to
 > it until the speaker
 > got up and pointed out what it was all about.
 >
 > 	Seems to me that the possibility of accidental
 > arcing is greater in a
 > TC jury rig than it was in this very professional
 > site.  While the total
 > quantity of inflammable material is vastly less it
 > could still make a
 > nasty mess with lots of wicked sooty smoke.
 >
 > 2. RG58 is pretty small stuff.  Why not RG-8 (solid,
 > not foam
 > dielectric) or  equivalent?
 >
 > 3. Even with the insulation on the wire I'd behave
 > around it as if it
 > were uninsulated.
 >
 > Ed
 >
 >