RE: Grounding Question

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

Original poster: "Ian McLean" <ianmm-at-optusnet-dot-com.au> 

Thanks Gary,  this clears up a matter of confusion for me.  I was getting
worried that I was doing the wrong thing connecting my NST cases to RF
ground after reading some posts here about grounding the NST to mains
ground, but logic seemed to dictate to me that, well, if my safety gap
fires, then I am dicharging 15,000 volts into mains ground which could fry
household mains equipment.

Rgs
Ian.

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, 30 October 2003 12:49 pm
To: tesla-at-pupman-dot-com
Subject: RE: Grounding Question


Original poster: "Lau, Gary" <gary.lau-at-hp-dot-com>

  >Original poster: "Mccauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com>
  >
  >The ground on your NST is a safety ground.  You should ground it to your
  >120VAC ground.
  >Not RF ground ! ! ! !

  >Remember, the ground on the NST is primarily for safety.  You don't want
  >the chassis to become electrically hot
  >due to internal short.  Ground the NST to your 115VAC ground.

I can't see touching the case of the NST, ever, when the coil is operating,
as I'd likely be hit with streamers from the top load.  Even without
streamers, it's just not a good place to put your hands.

But more importantly, consider what happens when the safety gap fires.  The
center terminal of the safety gap is connected to the NST case, so you're
suggesting connecting it to AC mains ground.  Should a streamer hit the
primary and cause the safety to fire, the connection you propose would
discharge that streamer to your mains ground.  I think it's better to
channel such events through the RF ground, which is why I advocate
connecting everything to RF ground.

Gary Lau
MA, USA