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: Bonding Station ground to Service Ground  (Read 3303 times)
K6NRT
Member

Posts: 7




Ignore
« on: October 13, 2014, 09:53:26 AM »

OK everyone, I am hoping to get some opinions on my grounding dilemma.

I have a newer home (built in 2012).  During construction, the electricians installed a ground rod into the slab foundation that is now inside a wall directly below the service entrance panel, and it is also bonded to the rebar of the slab.  You cannot access the ground rod directly.  Apparently this is how things are done nowadays.

To make matters worse, the service panel is surrounded on the outside by 20 feet of concrete in just about every direction as part of a large driveway, so running a wire there is going to be very difficult.

I am getting ready to drill in 2 ground rods for the shack, but I don't see how I am going to get the two systems bonded.  I can't just run wire to the other rod, as it's inside a wall in concrete.  The only thing I have at the moment is the grounding provided in the romex that powers the shack, which I would consider to be too small for proper ground protection.  The only viable place I can see tying in to the ground is to use the service panel's ground bus, but that means I have to get my bonding wire into the wall since the service panel is flush mounted.

Has anyone else had to deal with this?  If the bonding is just to ensure that the two systems remain at the same voltage potential, can the romex ground serve that purpose?  I have seen mention of a 6 AWG wire, but it's unclear if that means to bond the systems together, or to provide grounding to the shack's ground point/bus.

Any advice or insight would be greatly appreciated....

Logged
KD0REQ
Member

Posts: 1006




Ignore
« Reply #1 on: October 13, 2014, 10:37:47 AM »

the #6 minimum wire is supposed to bond to the ground bus inside the entrance panel.

if you are lucky enough to have had the builder run a conduit to the shack, pull it through there.

otherwise, you are plumb outta luck unless you get lucky using the old two-pipe trick (inner one water under pressure, outer suction with a junk wet-vac to bore a run under the paving.)  you could cut an "expansion joint, yeah, that's what it is, Mr. Inspector, really" for the ground wire... or do what tens of thousands of us have done, ground stuff at the shack to a ground field unique to it, and pray for sunshine.

pushing a flexible wire under 20 feet of concrete, on what is probably a base with random assorted construction junk scattered underneath, is like pushing a spaghetti noodle uphill in a hurricane.  no sense even trying.
Logged
AA4PB
Member

Posts: 12980




Ignore
« Reply #2 on: October 13, 2014, 11:34:03 AM »

Drywall is easy to fix. I've often cut a piece of drywall out at the edge of the electrical panel so I could get additional wiring into the panel. If you are careful you can cut out a piece and save it for re-use. Place a piece of furring strip across the inside of the hole and fasten it with a couple of drywall screws. Put the piece of drywall that you cut out back into the hole and fasten it to the furring strip. Then use tape and drywall mud to finish the drywall repair. Add a little paint and nobody will ever know.

Hint: Take the cut piece of drywall to Home Depot and they can match the paint color for you with their scanner.
Logged
KD0SFY
Member

Posts: 402




Ignore
« Reply #3 on: October 13, 2014, 04:55:03 PM »

OK everyone, I am hoping to get some opinions on my grounding dilemma.

I have a newer home (built in 2012).  During construction, the electricians installed a ground rod into the slab foundation that is now inside a wall directly below the service entrance panel, and it is also bonded to the rebar of the slab.  You cannot access the ground rod directly. 


There has to be a way to get to the rod for inspection.  If they used a plate, then there should be a thick wire, at least 6 AWG, coming up through the concrete somewhere. 

6 AWG cable is for bonding any supplemental ground electrodes (ground rods) to the primary ground electrode. 
Logged
K3GM
Member

Posts: 1824




Ignore
« Reply #4 on: October 15, 2014, 04:39:13 AM »

Why are you installing two ground rods at your shack location? If by that do you mean literally where the equipment is located?  For most stations, the safety ground in the house wiring is all that's required for your equipment grounds.

Transmission and control lines should have a lightning ground located OUTSIDE the structure at the entrance panel.  Do not bring that in inside.  That's where you want to drive ground rods in.  In addition, those rods must be tied to the dwelling's service entrance ground.  If the rod is embedded in the concrete wall, there must be a wire that exits the wall and ties to the service panel.  Make your connection there.  My house service entrance ground rod is just inside my garage at the breaker panel.  To access that rod, I drilled a hole through the 12" poured concrete wall to connect the #4 solid copper wire from my station's entrance panel and tower grounds to the wire connected to the ground rod.  I did not disturb the service ground rod or connector. You'd be amazed at how fast a Hilti hammer drill will penetrate 12" of reinforced concrete.  I had to cross two garage door entrances to get there.  I stuffed the wire into the seam between my driveway and the concrete apron of the garage floor. I could have very easily connected the station ground to the  service ground from inside the house.  But to do that is inviting the "fire" inside.  Keep it outside.
Logged
K1CJS
Member

Posts: 6055




Ignore
« Reply #5 on: October 15, 2014, 01:17:10 PM »

AA4PB has it right.  If you can bond to the ground cable just outside of the electrical panel with your #6 cable to the shack ground system, you've done what is recommended.  Even if you have to run that ground cable (to the electrical panel) along joists or fish it through the wall, it is better than not bonding the two ground systems together. 

Forget the tales about not running ground cable inside the building--if that's what has to be done to conform to the NEC, then it has to be done.  It's better than having two potentials inside the shack--where you may become the connecting link between them!
Logged
WX7G
Member

Posts: 6197




Ignore
« Reply #6 on: October 16, 2014, 05:22:09 AM »

http://www.joneseducation.com:8080/xyleme_cre_player/courses/ncti/ep1101_01_dt/Scorm2004Content/media/DirecTV/Grounding/NEC_Section_810_Excerpt.pdf

Logged
K9RJ
Member

Posts: 35




Ignore
« Reply #7 on: October 21, 2014, 10:35:48 AM »

WX7G, thank you for posting the document. Harris K9RJ
Logged
K1PJR
Member

Posts: 148




Ignore
« Reply #8 on: October 22, 2014, 04:37:55 AM »

Ok I'll be the odd man. I don't ground my equipment. I have a long wire. Disconnect when not in use. I've read many articles on grounding and many are confusing but I've never had an issue. My shack is on the second floor and the ARRL handbook even says you should not bother with a station ground in my case. The long ground wire could act as a radiator.
Logged
W9FIB
Member

Posts: 892




Ignore
« Reply #9 on: October 22, 2014, 08:31:36 AM »

Ok I'll be the odd man. I don't ground my equipment. I have a long wire. Disconnect when not in use. I've read many articles on grounding and many are confusing but I've never had an issue. My shack is on the second floor and the ARRL handbook even says you should not bother with a station ground in my case. The long ground wire could act as a radiator.

WX7G posted the NEC code book section that deals with this. While I consider it as a minimum, it is what is required by law unless you are in a very rare place in the US where the NEC is not incorporated in the local building codes.
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!