[R-390] Ham Shack Grounding Help!!!!

Fri, 21 Jun 2002 09:06:53 -0700

Jim,  I bet this is a dead horse ready to ride.... the thought of having a
ground pipe under my desk or workbench conjures up the image of working on a
radio while standing in the bathtub filled with saltwater.. I offer this as a
consideration,  not as a criticism.  I'd prefer to have a good ground where I
can see it and not necessarily become intimate with it.    I'm sure your system
serves you well and I admire your effort in implementing it.  If I had a lot of
equipment in fixed locations,  it might serve me.  My main concern when working
on anything electrical is to keep all parts of my body at a single potential and
to avoid the accident of touching different parts of me to different
potentials.  Half of the concern is the location of ground relative to my body.
The other half is keeping out of touch with the "high" potential areas.  On a
lot of projects on old radios,  I use a fused isolation transformer so I know
earth ground is not part of the equation as far as the electrical mess that is
setting in front of me.  Maybe I need to rethink whether your system could help
me - one problem I have is getting a reliable "water pipe" type ground
connection into my radio area. Dan

Jim Brannigan wrote:

> One should never rely on the outlet ground, there are just too many
> variables.......
> My station ground is based on the Handbook model.
> A 1/2 inch copper pipe is mounted under the desk and braid is run from the
> pipe to EACH piece of equipment.  A heavy wire is run from the copper pipe
> to the earth ground system.
> On installation, the ground braid is connected to the chassis before the
> radio is plugged in.
>
> As an additional safety feature, the Shack outlets are connected to a DPDT
> wall switch.  In the off position, all radios are electrically dead......
>
> Jim
>
> ----- Original Message -----
> From: "Dan Merz" <[email protected]>
> To: "Roy Morgan" <[email protected]>; "R-390 List" <[email protected]>
> Sent: Friday, June 21, 2002 01:34
> Subject: Re: [R-390] Ham Shack Grounding Help!!!!
>
> > Roy/Kim,  I can agree with the 60 v normal when there's no grounded
> outlet - I
> > have pretty modern wiring in my home but one day not too long ago
> discovered  60
> > volts chassis to ground even though it should have been zero.  I
> discovered this
> > by   rf noise associated with touching a wire from an external ground rod
> located
> > outside the house to the radio chassis,  and then measuring about 60 volts
> ac
> > between the chassis and the ground wire.    It took me awhile to discover
> that on
> > the leg of my wiring where I have my radios there was no ground coming to
> the 3
> > prong outlet or to any of the several other outlets on the same circuit -
> easily
> > detected by plugging in one of the circuit checker gadgets - but not so
> easy to
> > remedy.  Fortunately I was able to get into the junction box where the
> problem
> > originated (conveniently left somewhat visible by the previous owner) and
> found a
> > ground wire that was not firmly connected to the bundle of ground wires
> connected
> > there.  Too many connectors in an undersized wire nut and with no room to
> tighten
> > it sufficiently !!  I fixed that by better type of connection and the 60
> volts
> > went away.   I feel safer now.  I guess if  one of those caps( the one on
> the hot
> > side)   that put the 60 v on the chassis happens to short,  I'll now be
> saved by
> > my circuit breaker or radio fuse rather than taking the potentially lethal
> > current myself if I happen to be grounded.       Dan.
> >
> > Roy Morgan wrote:
> >
> > > At 11:21 PM 6/20/2002 -0400, you wrote:
> > > >I have received lots of good info that I can use to help eliminate my
> noise
> > > >problems.  I was out all day today so did not get to follow up on any
> of
> > > >this.  Yesterday however I did do one check and it did not look good.
> There
> > > >is 60 v. from the chassis of my radio to the cold water pipe.
> > >
> > > Standard condition.
> > > Caused by NORMAL operation of the line filter capacitors.
> > > GROUND your radio to the cold water pipe, PLEASE.
> > > Do not use any ground fault interruptor outlets.
> > >
> > > >  Not good at
> > > >all.  I am going to get an electrician in here as soon as possible to
> see
> > > >what we are going to have to do to fix that.
> > >
> > > That is cused by the RADIO line filter. NOT by the electrical system in
> > > your house, except that you have ungrounded outlets.
> > >
> > > Roy
> > >
> > > Roy Morgan
> > > K1LKY since 1959
> > > 7130 Panorama Drive, Derwood MD 20855
> > > 301-330-8828 home .... 301-975-3254 work
> > > [email protected]
> > >
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