Re: grounding question

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Good for you Jim,

If you or anyone else only connects the safety ground to the variac 
(or control panel) and dont connect it to the NST or  PIG chassis, or 
counterpoise (and many may not want to do this to protect their house 
wiring), then these items must be considered dangerous and off limits 
while the system is plugged in.  Of course, I dont want to come 
anywhere close to a PIG even if its case is grounded with the green 
wire.  Them high voltage bushings are mighty intimidating :o)))

Gerry R.

> Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
>
> Big green ground in place! Trip those breakers for life.
>
> -----Original Message-----
> From: Tesla list [mailto:tesla@xxxxxxxxxx]
> Sent: Saturday, October 14, 2006 8:43 AM
> To: tesla@xxxxxxxxxx
> Subject: Re: grounding question
>
> Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
>
> Hi Jim, Not sure which Jim
>
> I think I figured out the issue after replying last nite.  The issue
> is NOT GROUND.  The issue is NEUTRAL.  You can short the HOT to earth
> ground and nothing happens other than some current flows (assuming no
> GFI).  Only if you short the HOT to NEUTRAL will the breakers
> pop.  If an instrument case is RF grounded and HOT becomes shorted to
> case, there is no guarantee the breakers will pop because the earth
> ground impedance is too high.  If the case is green wire grounded,
> enough current will flow to trip the breaker hence line safety is
> provided. If the breaker box is ungrounded (lets say because the
> ground has dried out, the green wire is still connected to NEUTRAL at
> the box which is a low impedance return for the line.  Safety is
> provided by the green wire connection to NEUTRAL. The Whole point true with
> appliance faults too in a fault condition, Yes! <snip>