[Sneap] RG58C/U max dc voltage?

[ThunderHooves]

The polyethylene insulation in RG58C/U cables will withstand 1kV DC per 0.001" as a rule of thumb. It would only take 0.010" or 0.25mm of insulation thickness to keep the cable from breaking down. The insulation is much thicker than that. The tracking standoff along the surface of polyethylene (or any other smooth insulator) is about 10kV DC per inch. The connectors probably have more than an inch of tracking surface between any two conductors if they are rated to 10kV. In your switching application you have the potential to produce 20kV pulses if you have any open circuit reflections. This should be your concern. If you want to test it, strip the two ends of a section of RG58C/U two inches, connect one end to a 20kV supply, and turn it on. It will probably hold more than 20kV. Also, test it with the SHV connector attached.

Gregory C. Harper               Phone:(206) 543-4084 (Office)
Research Engineer/Scientist IV        (206) 543-4062 (Lab)      
University of Washington        FAX:  (206) 685-4634
CENPA NPL Bldg.
Box 354290                      email: gharper at u.washington.edu
Seattle, WA 98195-4290

On Wed, 12 Mar 2008, Hjalmar Bruhns wrote:

> The host for the 2008 SNEAP annual meeting is the University of Michigan at Ann Arbor.  The meeting dates are: October: 10 - 16, 2008.
> The meeting web link is:
> http://www-ners.engin.umich.edu/research/Mibl/Sneap/2008.htm
>
>
> Dear SNEAPers,
>
> Does anyone know how much DC voltage a RG58C/U cable is spec'd to handle?
>
> SHV-10 connectors like the Kings 1065-1
> http://www.kingselectronics.com/HighVoltage/connectors/tabid/52/laproduct/351/default.aspx
> are rated to 10kV "for use with RG58C/U cable". But the bit of info I find
> on RG58C/U concerning voltage is "Max. Voltage 1900 Volt" - although that
> probably applies to RF applications, not DC.
>
> We intend to switch our ~8kV on and off with up to 5kHz using HV switches
> that have ~100ns switching times.
>
> Can we trust RG58C/U to handle that?
>
> Thanks,
>
> Hjalmar
>
> --
> Hjalmar Bruhns
> Columbia Astrophysics Laboratory
> Nevis Laboratory/Cyclotron building
> 136 South Broadway
> Irvington, NY 10533
> tel: +1-212-854-1449 (Campus)
>      +1-914-591-2874 (Nevis)
> fax: +1-212-854-8121
> email: hbruhns at astro.columbia.edu
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