Shielding HV Leads

[W9ZSL]

I often see schematics showing shielded wire for high voltage lines.  I've heard that coax can be used.  If so, what type or is there an alternative?

[N2DTS]

Was done in the past for TVI reasons, not sure you have to worry about it now.

[W3GMS]

I often see schematics showing shielded wire for high voltage lines.  I've heard that coax can be used.  If so, what type or is there an alternative?

Over the years I have seen HV being distributed through RG-8 cable.  One can debate the issue of doing it to begin with, but here is a document which you may find useful. 

http://www.spellmanhv.com/en/Technical-Resources/Application-Notes/AN-07.aspx

Joe GMS

[W1ITT]

For most of the voltages that Radio Amateurs may deal with, it isn't the cable that's the problem, but the connector at each end, and how well it's prepared.  I have used Type N and Type HN at 6 kv, and I have popped both in the past too.  I think the HN is only "officially" rated at 1500 volts.   
There are specialized high voltages connectors such as Alden and Reynolds at Surplus Sales of Nebraska, but none of them are cheap.  The Millen HV connectors have always scared me.
If you decouple the HV where it leaves the transmitter with a series choke and parallel capacitor network, shielding shouldn't be necessary, but it gives me a warm fuzzy feeling to have a sold ground between me and the plate voltage.

[W9ZSL]

I'd rather not mess around with HV shielding at all since everything will be caged and in an Atlas cabinet.  I can see using those HV connectors but at $20 a pair they get expensive.  I have many feed-through ceramics that would work and am not concerned with the HV only the break-down voltage of the feed throughs.

[WQ9E]

The only time I would be concerned about shielding HV cable is when the power supply is separate; the shielding would be for safety in this case.

[W9ZSL]

Everything is going to be in the same cabinet.

[W9ZSL]

I was wondering about those Millens.  I'd rather go with my ceramic feed-throughs since I have a lot of them.  That way I can mount the S-22 terminals down and avoid crud build-up.  TVI is less a problem now that everything is digital but even at that I have a NOS still-sealed B&W low-pass filter that I can hardly wait to liberate from it's plastic bag!

[WU2D]

The separate racked PSU for the ART-13 has the HV going through an ordinary 15 ft run of RG-59 75 ohm coax and it has been working great since 1992.

[KJ4OLL]

Hi,
As previously mentioned, the connector is where the HV problem breaks down;)

I use these connectors on my HP 6525A High Voltage DC Power Supply (4kv output).
Easy to find, not too much $$$.

 http://en.wikipedia.org/wiki/MHV_connector

http://www.mouser.com/Search/Refine.aspx?Keyword=mhv+connector

73
Frank

[Opcom]

The braid from some old coax ought work to slip over whatever wire someone uses.
I use 15KV outdoor rated luminous sign wire and the traditional ceramic feed through insulators with the bolt and nut accepting a wire lug.
That wire is 16 or 14 gauge IIRC and a spool was cheap.
Those are all enclosed when the cabinet doors are shut so no worry.

The one unit here with a separate supply (5KV wire from it to the load) uses 20KV insulated wire covered by grounded braid and also the expensive type non coaxial HV connector.