grounding power supply email trail is confusing

[Jim Spears]

K9YC, W3FPR, W4TV and others have certainly raised my interest in the art
and science of "grounding" vs "earthing" in the grand scheme of things as
specified in the NEC and other sources.  But there has been such a
proliferation of messages over several days, the net effect of which is to
leave me massively confused.  Could someone synthesize this into a set of
practical guidelines which are NEC compliant and technically correct.  

 

While surveying the stuff in my shack, I see boxes with two connector
unpolarized plugs, two connector polarized plugs, three conductor plugs with
a ground stud, and three conductor plugs with no ground stud.  In my shack I
have a mix of 240 and 120 vac boxes.  These are on separate circuit
breakers, the main panel is located at the opposite end and one floor up of
a fairly good sized house.  Just for fun, I have copper pipes but the well
pipe is plastic.\

 

Jim/N1NK

K3/100 2295

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Byron N6NUL]

On Jan 22, 2010, at 9:37 AM, Jim Spears wrote:

> Could someone synthesize this into a set of practical guidelines which are NEC compliant and technically correct.

I'm starting with the ARRL 2010 Handbook, Chapter 28 - Safety.  Grounding is discussed extensively beginning in section 28.1.8.

Byron KI6NUL
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Jim,

Maybe Eric will not object if I summarize my views in one last public
post. :-)

There are 3 "grounds" that a ham station should be concerned with:
1) AC service grounding - best to consult with a licensed electrician on
this one.  Older buildings may need some updating.  Unless you have
knowledge of NEC, this is not a 'do it yourself' job.  A local
electrician should know the current code requirements.
2) Lightning grounding - reference the articles in QST during 2002 or
other authoritative sources (Polyphaser site, etc.).  No license
required to install, but it must connect to the utility entry ground to
meet code and be safe.
3) RF Ground - IMHO, difficult/impossible to create with an earth
connection (but many try), so solve the problem in the antenna field by
balancing the currents and the RF Ground should take care of itself.

73,
Don W3FPR

Jim Spears wrote:

> K9YC, W3FPR, W4TV and others have certainly raised my interest in the art
> and science of "grounding" vs "earthing" in the grand scheme of things as
> specified in the NEC and other sources.  But there has been such a
> proliferation of messages over several days, the net effect of which is to
> leave me massively confused.  Could someone synthesize this into a set of
> practical guidelines which are NEC compliant and technically correct.  
>
>  
>
> While surveying the stuff in my shack, I see boxes with two connector
> unpolarized plugs, two connector polarized plugs, three conductor plugs with
> a ground stud, and three conductor plugs with no ground stud.  In my shack I
> have a mix of 240 and 120 vac boxes.  These are on separate circuit
> breakers, the main panel is located at the opposite end and one floor up of
> a fairly good sized house.  Just for fun, I have copper pipes but the well
> pipe is plastic.\
>
>  
>
> Jim/N1NK
>
> K3/100 2295
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ------------------------------------------------------------------------
>
>
> No virus found in this incoming message.
> Checked by AVG - www.avg.com
> Version: 9.0.730 / Virus Database: 271.1.1/2638 - Release Date: 01/22/10 02:34:00
>
>  

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Jim Brown-10]

On Fri, 22 Jan 2010 09:48:45 -0800, Byron Servies wrote:

>On Jan 22, 2010, at 9:37 AM, Jim Spears wrote:

>> Could someone synthesize this into a set of practical
guidelines which are NEC compliant and technically correct.

>I'm starting with the ARRL 2010 Handbook, Chapter 28 - Safety.
>Grounding is discussed extensively beginning in section 28.1.8.

That's a very good reference. Parts of the 2010 Handbook was
extensively updated, and this part of it was written by Jim Lux,
W6RMK, a very smart engineer who works at JPL (Jet Propulsion
Laboratory, where they design stuff for the US Space program). I
haven't had time to study it, but I'd bet that it's quite good.

My own work on this is in the Grounding chapter in K7LXC's
excellent book on towers, and on my website in the Power and
Grounding White Paper commissioned by SurgeX. The SurgeX White
Paper is specifically written for audio and video systems, so its
coverage of antennas is limited to those applications, while the
material in the K7LXC book is specifically directed to homes with
a ham shack.

I suggested that a picture is worth a 1000 words

Gee -- I included a link to the Power and Grounding White Paper,
and another link to a power point with drawings showing the
leakage current issues. Was that not enough for you? :)  

>and here is a
>leaflet from the RSGB which explains some of the subject for UK
>amateurs.  I'm sure there's a similar leaflet from ARRL and other
>societies.

>http://www.rsgb.org/emc/pdfs/leaflets/emc_leaflet07.pdf

It should be noted that power systems, legal requirements and
practices vary from one country to another. I recently expanded
the Power and Grounding White Paper I wrote for SurgeX to include
European power systems.

73,

Jim Brown K9YC



______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html