Re: Coax Cable for High Voltage?

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

Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jimlux-at-earthlink-dot-net>


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, February 27, 2001 6:14 PM
Subject: Re: Coax Cable for High Voltage?


> Original poster: "R Lunsford by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Millipede-at-carolina.rr-dot-com>
>
> As far as the coax goes, I personally wouldn't use it. I really isn't
> designed for it.

To the contrary, most larger coax cable is designed for high voltage.  In
fact, they are rated at a variety of voltages 5000 VRMS would be typical for
RG-213/RG-8 series, with 11000Vrms for the next size up.  And, recall, that
that rating is for use in a transmitter, where you might have standing waves
that are substantially higher.

I wouldn't try running HV down RG-174 of course, and as previously pointed
out, I would stay away from the various foam insulated varieties (RG-8X,
8813, TMR400,etc.), although, by definition, those probably have the same
ratings, since they are intended as "work alike, but lower loss"
replacements.

A fairly quick calculation of the field strengths will show that RG-213 can
take a fairly high voltage.

I personally like grounding the shield, because it makes the field more
uniform, and provides a safety aspect that if there is a fault in the
dielectric, it's going to short/arc/spark to the shield, not my hand.