Grounding

[mmckenna]

I just found this thread, and noticed that no one answered your question. There a number of ways, but a popular way is to use an impact driver. Here is a video, showing how someone has made a tool, that minimizes impact damage to the top of the rod.

Back when I was in installation, we used these:

SDS Max Ground Rod Driver - - Amazon.com

SDS Max Ground Rod Driver - - Amazon.com

www.amazon.com

A big Milwaukee SDS drive hammer drill would nail in a ground rod no problem.
I seem to recall we had an electric demolition hammer that had a rod driver attachment, also.
Both worked very well.

When I had to drive my own, I purchased on of these at Tractor Supply:

https://www.tractorsupply.com/tsc/product/speeco-post-pounder-s16110900

You can also use a large hammer, but it can take a while and your arms will get tired.

 

[merlin]

When I have seen service ground like that the ground rod is laid on ground with rebar and the foundation pored over that. A bend just above the foundation to attach the ground wire to the power service box.
unless code has changed, at least 14AWG solid copper wire is used. electrical supply houses have clamps you could use to attach your ground wire to the shack. Get as close to the foundation as you can, if not to the rod itself. Use at least the recommended 14 solid copper wire or equal with braid.
I would not consider a non conductive mast and you can route ground wire through the chimney to a bracket or clamp to the mast. A series lightning arrestor, grounded where your feed enters the shack.

 

[merlin]

Back early 80s, putting up a repeater on Angel peak, a slab with nothing is where we started.
We drove a good half dozen rods fanned and connected and used the rod driver(drill driver)
similar to this https://www.tractorsupply.com/tsc/product/speeco-post-pounder-s16110900
It will do the job even in rocky hard soil.

 

[WB9YBM]

I'm not sue how many people own an impact driver; I've pounded in my fair share of ground rods using nothing more than a hammer (assuming the ground's not too hard--might need softening up with some water).

As for not hitting any pipes--I think in many cases telephone numbers exist ("1-800-Julie" in the Chicago area) that's sort of a hot-line for the gas / power companies they tell us to call before anyone does any digging--maybe there's a similar number in your area. As for actual pipes, maybe someone like your city's planning commission has files handy on your property that might show water pipe locations...

 

[mmckenna]

I think in many cases telephone numbers exist ("1-800-Julie" in the Chicago area) that's sort of a hot-line for the gas / power companies they tell us to call before anyone does any digging--maybe there's a similar number in your area.

Call811 | Know what’s below. Call before you dig.

811 is the national call-before-you-dig phone number.

call811.com

 

[lenk911]

Placing ground rods in concrete is not recommended for lightning protection. This was popular with tower construction in the 50's. The concrete's chemistry locks water molecules in chemical bond and a lightning strike would cause the concrete to explode.

 

[prcguy]

Ground rods going through a small isolated foundation and taking a direct lightning hit can blow the concrete apart but today its very common practice to bond the rebar inside concrete to the lightning ground to supplement the ground system. Its called an Ufer ground and in many areas the code for new home construction requires bonding the foundation rebar to the house electrical entry point. The larger you can make the ground system including rebar in concrete, the lower the impedance you will have and the better it will dissipate a lightning strike.

Placing ground rods in concrete is not recommended for lightning protection. This was popular with tower construction in the 50's. The concrete's chemistry locks water molecules in chemical bond and a lightning strike would cause the concrete to explode.

 

[WB9YBM]

today its very common practice to bond the rebar inside concrete to the lightning ground to supplement the ground system.

How much resistance does concrete present between the rebar and ground?

 

[lenk911]

You need to separate your thinking between NEC safety ground requirements from that of lighting protection of a communications installation. If you have a million dollar radio installation you don't protect it with a Ufer ground! These installations have typically 12-20 ground rods spaced 2xrod depth apart all intertied together. Along the Great Lakes, I add a 120 foot dry well to the mix.

 

[prcguy]

An Ufer ground is never your single or main ground, it supplements a ground system. And it is used in many installations including $100 million dollar and up.

Your description of 12-20 ground rods would be for a small shack at the base of a tower like a cell site. A big system will have hundreds of ground rods and thousands of feet of buried bare copper cable.

You need to separate your thinking between NEC safety ground requirements from that of lighting protection of a communications installation. If you have a million dollar radio installation you don't protect it with a Ufer ground! These installations have typically 12-20 ground rods spaced 2xrod depth apart all intertied together. Along the Great Lakes, I add a 120 foot dry well to the mix.

 

[prcguy]

I've never measured one by itself. I will guess it depends on how much moisture content it has and how old it is. I suspect its not much worse than soil and its defiantly low enough resistance to include in the overall ground system and its a code requirement in many areas.

How much resistance does concrete present between the rebar and ground?