I'm a little confused by Martin's question.
I thought the whole idea behind an SPG was to not only
MAKE SURE the two grounds were connected, but to
eliminate the distinction.
Have I missed something?
73, kelly
ve4xt
> From: "Keith Dutson" <kjdutson@earthlink.net>
> Date: 2005/02/25 Fri PM 03:39:09 CST
> To: <towertalk@contesting.com>
> Subject: Re: [TowerTalk] Ground system design, RF
vs AC
>
> >If you cross-connect your ham & AC power grounds,
any such fault currents
> will flow in your ground system too, for better or
worse.
>
> AFAIK, every piece of ham gear that uses a three
prong AC cord has the
> safety (green) wire securely attached to the chassis.
If you attach a
> ground strip from the chassis to the ham system
ground, does this meet your
> definition of "cross connect"?
>
> Keith NM5G
>
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On
Behalf Of Martin AA6E
> Sent: Friday, February 25, 2005 3:11 PM
> To: keith@dutson.net; towertalk@contesting.com
> Subject: Re: [TowerTalk] Ground system design, RF
vs AC
>
> Keith,
>
> I believe "fault" is the general electrical term for power
going where it
> shouldn't. That's why we have protective system
grounds in AC systems. If
> there is a short circuit in an appliance connecting the
hot side to the
> chassis, a fault current flows in the ground lead and
the user is protected.
>
> A GFCI detects even tiny fault currents and shuts off
the circuit asap.
> (It detects a difference between hot & neutral current,
as you
> suggest.) That's a good thing, but old-fashioned fault
protection involves
> blowing the upstream fuse or breaker with an
overload current.
> That's one reason why your branch circuit wiring has
to be matched to your
> breaker - to be sure it will trip quickly if there is a
short.
>
> If you cross-connect your ham & AC power grounds,
any such fault currents
> will flow in your ground system too, for better or
worse.
>
> -Martin (who is not an electrician)
>
> --- Keith Dutson <kjdutson@earthlink.net> wrote:
>
> > You wrote:
> > >The problem with connecting the AC green wire to
the radio room
> > ground and
> > then connecting my bulkhead "SPG" to a new
ground rod or even a
> > perimeter ground connection is that my radio
installation becomes part
> > of the AC protective ground system for the house.
That is, any house
> > fault or other current will partly be routed through my
radio ground
> > system. Is that what we want?
> >
> > When you say "house fault" I assume you are
referencing a ground
> >fault circuit interrupter (GFCI) system. Such a
system interacts with
> >the white neutral ground, not the green safety
ground. So the answer
> >is yes, we do want the safety ground connected.
> >...
>
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> See: http://www.mscomputer.com for "Self
Supporting Towers", "Wireless Weather Stations", and
lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
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Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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