[AMRadio] HV Wire


Jim Candela jcandela at prodigy.net
Thu Dec 21 13:59:31 EST 2006


Jack,

   The HV wire type needs to be sorted by the application. What I use inside a RF deck or Modulator deck would be different than external wiring between say a floor mounted power supply and a RF deck. 

   Within a chassis, I would rather use air insulation, and ceramic standoff tie points. Adding extra insulation to existing wires is easy with Teflon sleeving slipped over the wires. Sometimes the old wires have decrepit insulation, and the sleeving is sometimes an easier way to repair something. For HV at my work, one application uses 22 awg Teflon wire inside Teflon sleeving that the wire just fits into. We use 3 kv this way without incident. Using Tygon or PVC sleeving will help, but the safety factor is as you said, is hard to predict.

  Between two chassis HV wiring is different. There I prefer shielded cable where the braid is grounded. You can home brew your own, but polyethylene coax cable is good here when the HV is DC. There is a connector similar to a BNC called MHV that is rated for 5 KV, and intended for use with RG-59 (not foam). This way, things are very safe, and easy to connect / disconnect.  

BTW, RG-8 or RG-214 (neither foam) are routinely used in industry for up to 40 Kv without failure. The trick is at the terminations to keep the spacing right. There is a modified PL-259 plug and SO-239 socket designed for this purpose. The AC RMS rating of coax is much lower than the DC capability (often not rated).

Hope this helps,
Jim
JKO


Packard 440 wire, wasn't that off an old Packard, or was it a Hudson? ;-)


----- Original Message ----
From: Jack Schmidling <jack at schmidling.com>
To: Discussion of AM Radio in the Amateur Service <amradio at mailman.qth.net>
Sent: Thursday, December 21, 2006 9:28:55 AM
Subject: [AMRadio] HV Wire

Seems to me that inserting common lamp cord into clear PVC tubing, like 
1/4" id, 3/8" od would make an easy to work and readily available HV 
wire and also serve the purpose of grommets.

Problem is, I haven't a clue and can't seem to find any info on the 
insulation resistance of this tubing.

My guess would be several tens of thousands of volts.

Anyone have any real info?

js







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