Re: HV xray cable revisited

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

I'd be careful handling it even when not in operation.
Whether the shield is grounded or not, there's some
amount of capacitance between the shield and the
conductor. It may retain a slight charge whether it's
grounded or not. At work, we have to discharge our 12
kV feeders before we can work on them, as there's
enough capacitance to retain quite a charge. This
probably isn't a problem with the relatively short
runs we use, but it might be if someone has a fairly
long run that they don't want to cut.

Has anyone ever measured the capacitance (or residual
charge) of their cable?

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: "Barton B. Anderson"
> <bartb@xxxxxxxxxxxxxxxx>
>
> Hi David,
>
> The cable grounding is to prevent the cable from
> arcing to objects
> where the cable is routed. Mains or RF ground will
> do for this
> prevention. If the cable has a high probability of
> strikes (strikes
> that reach floor fairly well), then I would likely
> tie the braid to
> RF ground. In either case, it's not safe to be
> handling the cable
> while the coil is operating.
>
> Take care,
> Bart
>
> Tesla list wrote:
>
> >Original poster: "David Rieben"
> <drieben@xxxxxxxxxxxxxxx>
> >
> >Gerry,
> >
> >You raise a good point. However, it seems to me
> that with the low
> >occurances of direct streamer strikes to
> >the cables during operation that this should not be
> a big
> >concern.? I suppose I'm thinking more of personal
> safety
> >as well, going back to the mains ground. Anyone
> else like
> >to "jump in" on this discussion..... ?
> >
> >David Rieben
> >
> >
> >----- Original Message ----- From: "Tesla list"
> <tesla@xxxxxxxxxx>
> >To: <tesla@xxxxxxxxxx>
> >Sent: Sunday, January 08, 2006 10:26 AM
> >Subject: Re: HV xray cable revisited
> >
> >
> >>Original poster: "Gerry  Reynolds"
> <gerryreynolds@xxxxxxxxxxxxx>
> >>Hi David and all that are interested in this
> thread,
> >>Puting the Blumlien effect aside,  I have wondered
> what people
> >>think about grounding the outer shield of the
> cable to RF ground
> >>instead of mains ground.  The advantage I see is
> if a secondary arc
> >>makes it to the cable, the current will be
> returned to the base
> >>directly and not thru the mains ground.
> >>Gerry R.
> >>
> >>Original poster: "David Rieben"
> <drieben@xxxxxxxxxxxxxxx>
> >>As I said, I do ground
> >>the outer braids of both to the mains 60 hz ground
> and the ex-
> >>terior tank of the pig.
> >