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I have a question about the NEC's ground bonding code.

Thirsty

Thirsty

New amateur
Jan 27, 2011
105
4
28
Western Wisconsin
I have been doing much reading about grounding antennas etc. Now I understand multiple grounds need to be bonded together including the ground entering the house.
Now my question is , my 8 ft ground rod connected to the antenna mast which is connected to the coax via antenna, which is connected to my radio which is plugged into the wall socket ground which is connected to the electrical panel which is directly connected to the house ground rod, is this not bonded?

In order for me to run a wire from the antenna ground rod to the ac ground rod I will have to go all the way around the house and under a two car wide cement driveway.
I probably already know the answer but I believe it is "bonded" ,not with #6 copper wire though, but #12 romex through the house wire none the less.

This whole bonding discussion has me peeved.
 

It is connected but not bonded. Sounds odd doesn't it? Bonding generally refers to a heavy conductor with minimal voltage drop. In your case you have two grounds connected by a relatively small conductor, the coax cable shield. When lightning strikes the electrical potential of theground actually raises above "ground" as the current sweeps thru the earth. This causes the two ground points to have different voltages present on them and because of this a current will actually flow from one ground point to the other thru whatever is connecting them together. Now in you case you have all that lightning current wanting to flow thru your coax cable shield, into your radio, and out to the AC wiring to the ground at your AC service panel. If all grounds are tied together in one place and they all use heavy strap or wire then the voltage drop is very tiny and current cannot flow from one ground point to another. Believe me, lightning grounds are a science all unto themselves.
 
I understand what you are saying Captain K , I wish I had an easy way to accomplish this bonding. Maybe if I sit in the dark quietly long enough something will come to me other than trying to tunnel under my driveway.
 
Another way of looking at it is, can you move the house's ground point to the antenna's ground point? That's probably just as 'bad' as getting under that concrete... ;)
- 'Doc
 
Control Joints - Expansion Joints -- Movement Joints | Tile Your World

a driveway that large should have relief joints . typically 1x4 wood that allows the concrete slabs to settle without cracking . you could use a carbide circle saw blade .... slightly bend the teeth out a little each way alternating . use a scrap piece of wood to test for fit , but make it wide enough for the ground wire to go in . you dont have to go deep , a inch will be more than enough . cut along the length of the 1x4 and put the ground wire in there . use some u nails to hold it in place and cover the top with concrete patching calk . ive never done it ........ but it should work .

if you dont have relief joints get a concrete cutting circle saw blade and a chalk line (to keep it straight) and make some .
 
BOOTY MONSTER said:
Control Joints - Expansion Joints -- Movement Joints | Tile Your World

a driveway that large should have relief joints . typically 1x4 wood that allows the concrete slabs to settle without cracking . you could use a carbide circle saw blade .... slightly bend the teeth out a little each way alternating . use a scrap piece of wood to test for fit , but make it wide enough for the ground wire to go in . you dont have to go deep , a inch will be more than enough . cut along the length of the 1x4 and put the ground wire in there . use some u nails to hold it in place and cover the top with concrete patching calk . ive never done it ........ but it should work .

if you dont have relief joints get a concrete cutting circle saw blade and a chalk line (to keep it straight) and make some .
Click to expand...

Yep, it has thin expansion joints Booty Monster, something else to think about. The driveway is in good shape but next time around I will make sure to throw a piece of conduit under it.

So in everyone's opinion would it be better to 'not' ground an antenna than ground it and 'not' have it bonded? And what about these guys who have ground radials running all around the yard? My head spins.
 
If the ground under your driveway is not hard packed chert or is not full of some other aggregate stone you can tunnel under it with water.

You purchase 3/4" galvanized piping at Home D or Lowe's and adapt your garden hose to one end and start ramming it under the driveway by hand. I have successfully bored 40' using this method.

Done this for years to bore under sidewalks and driveways, but remember it will not work in hard packed chert or gravel bases.

Will not be easy, but it can be done.
 
"...would it be better to 'not' ground an antenna than ground it and 'not' have it bonded?"

The problem with not being 'well bonded' is that after the first 'strike' (or near one that stresses that join) that join should be re-done, it's probably not very good anymore. Another aspect would be that a 'little' grounding is better than no grounding, but that certainly doesn't make that 'little' bit very good at all.
When it becomes impractical to do, then figure another way to do it. Not very easy/simple maybe, but what's the alternative?
- 'Doc
 

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