Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Grounding question  (Read 1441 times)
N3CSA
Member

Posts: 25




Ignore
« on: December 05, 2010, 07:19:34 AM »

Currently, each piece of equipment has a separate ground wire running through the wall to the ground bar just outside, where they all terminate (and the suppressors are located).

With more equipment being added to the shack, I am wondering if I can instead install a single copper grounding bar on the inside wall, have it bonded via a cable to the outside ground bar, and run a ground cable from each piece of equipment to the (new) inside grounding bar.

This sure would make it easier to ground new equipment, and remove some wire clutter.

But, I am concerned that this may not be as good a grounding system as running a separate cable through the wall as I have it now?
Logged
AA4HA
Member

Posts: 1377




Ignore
« Reply #1 on: December 05, 2010, 08:01:21 AM »

That is how commercial sites are done. Just make sure that the conductor between the bus bar and the ground rod is of sufficient current carrying capacity for all of the potential fault loads.

Tisha Hayes
AA4HA
Logged

Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
WA7NCL
Member

Posts: 625




Ignore
« Reply #2 on: December 05, 2010, 09:13:32 AM »

You need to consider the purpose of your ground.

All the equipment in your shack that has 3 prong plugs is safety grounded by modern 3 prong house wiring.

If you are doing it for lightning, you should be concerned about grounding at your suppressor and the suppressors characteristics.
The impedance of that ground better be lower than the path into your house or the lightning will just be "invited" into your shack.

If you are after the "mythical" RF ground you are dreaming unless wire lengths are short.

If you are trying to equalize potentials between the various boxes in your shack, then a bus between the boxes is what you are striving for.

Except for lightning or in the case of 2 wire plugs and house wiring, grounding has little functional value.  If you make sure common mode RF from antennas is controlled and you interconnect your system correctly, you will notice no benefits.

I have a multitude of radios and computers in my shack and don't have a big expensive ground system.  Everything works as long as my antennas don't have a common mode problem.  The antennas include coax and window line fed systems.  Several times I added new antenna, and when I was sloppy I had RF problems, but in each case attacking the common mode issue was the solution.

In the end most hams just ground things because other hams tell them to and the big bus bars and wires make them feel good.  So if you are in this camp, then just do what feels right.
Logged
KB9CRY
Member

Posts: 4284


WWW

Ignore
« Reply #3 on: December 05, 2010, 01:01:15 PM »

Currently, each piece of equipment has a separate ground wire running through the wall to the ground bar just outside, where they all terminate (and the suppressors are located).

With more equipment being added to the shack, I am wondering if I can instead install a single copper grounding bar on the inside wall, have it bonded via a cable to the outside ground bar, and run a ground cable from each piece of equipment to the (new) inside grounding bar.

This sure would make it easier to ground new equipment, and remove some wire clutter.

But, I am concerned that this may not be as good a grounding system as running a separate cable through the wall as I have it now?

Actually that's what most folks do, the single buss bar inside and run a bonding wire to the outside.
Logged
K1CJS
Member

Posts: 5851




Ignore
« Reply #4 on: December 05, 2010, 01:12:57 PM »

Using a busbar on the inside of your shack can be done.  That is the way a great percentage of ham shacks are set up.  I will assume that you have lightning suppression installed on your incoming co-ax leads already--if you don't, that is the first thing to attend to.

Some people insist that an inside grounding bus is best connected to the outside ground point by a flat copper strip.  Others say a single six or eight gauge cable will suffice.  What you do there is more a matter of preference than anything else.  Since it's kind of hard to connect a rig fed by 12 VDC to a house ground via a three conductor power cable, you will want to ground each piece of equipment to the ground bus.  The one thing you MUST do, however, to comply with the electrical code is to make sure the shack grounding point and the house electrical grounding point are connected together by six gauge copper cable--for safety sake. 

It would be a good idea to also be sure of the wiring to the shack, making sure the electrical ground from the shack outlets is connected to the electrical panel ground.  If you don't know how to do so, have an electrician check it out for you.
Logged
AA4PB
Member

Posts: 12666




Ignore
« Reply #5 on: December 05, 2010, 03:27:27 PM »

It is also a National Electric Code requirement that the radio grounding system be bonded (i.e. permanently connected) to the home's electrical system ground via at least a #6 wire.
Logged
W6RMK
Member

Posts: 649




Ignore
« Reply #6 on: December 05, 2010, 09:11:42 PM »

It is also a National Electric Code requirement that the radio grounding system be bonded (i.e. permanently connected) to the home's electrical system ground via at least a #6 wire.

I think that's not precisely true.  If you have multiple earth grounds, they need to be bonded appropriately.  But, for instance, if you've got a bunch of stuff sitting on a desk, there's no requirement it be bonded.  NEC is silent on things that are plugged into the wall, all "the code" cares about is whether that wall receptacle is properly wired.

There are also rules in Art. 800 about antennas, but frankly, most hams not follow them. 
Logged
K1CJS
Member

Posts: 5851




Ignore
« Reply #7 on: December 06, 2010, 04:50:44 AM »

It is also a National Electric Code requirement that the radio grounding system be bonded (i.e. permanently connected) to the home's electrical system ground via at least a #6 wire.

I think that's not precisely true.  If you have multiple earth grounds, they need to be bonded appropriately.  But, for instance, if you've got a bunch of stuff sitting on a desk, there's no requirement it be bonded.  NEC is silent on things that are plugged into the wall, all "the code" cares about is whether that wall receptacle is properly wired.

There are also rules in Art. 800 about antennas, but frankly, most hams not follow them.  

Jim, as written, the code requires all grounding points in and around a building to be connected together--bonded--with a six gauge cable.  All grounding points, not just all electrical service grounding points.  I believe that was written in to include lightning rod grounding points because of the danger of the charge jumping over and causing damage to the building.
« Last Edit: December 06, 2010, 04:54:39 AM by Chris J. Smith » Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!