[TowerTalk] Adding ground rods, effect on ground resistance..

kb9cry at comcast.net kb9cry at comcast.net
Mon Jan 17 14:36:47 EST 2005

I'll take a stab at these questions, based on my learnings.  Personally I use ICE devices in my installation and have thoroughly read through all the related Polyphaser and ICE articles, plus others.  Phil  KB9CRY

> I have three 8 ft ground rods at the base of my tower, connected to 
> each tower leg, 

Not enough ground rods per Polyphaser.  They recommend up to 85 feet worth of ground radials per tower leg, with rod every 2X rod length (16 ft between 8 ft rods).

>tied together by a nr 2 wire 

Not necessary per ICE; the tower itself ties them all together so nothing gained by tieing them together but also won't hurt.

plus tied to my rebar 
> cage in the concrete (the rods are outside the concrete base) per my 
> city bldg code. My coaxes pass through I.C.E. devices that are 
> connected to the very bottom of the tower. The coax runs underground 
> through a PCV tube to the house. At the house they pass through 
> Polyphaser devices before entering the wall that are connected to 
> another 8 ft single ground rod. 

Very nice, shields grounded at tower (some will argue that you should also tie them to the tower up top but no has convinced me that only at bottom is sufficient.)  Also, tie this SPG to your electrical entrance ground.  Route at least a bare #4 outside of the house avoiding sharp turns.  Cadweld connections are best.

There is 25 ft of coax between the 
> base of the tower and where it enters the house. 
> Question, should these two grounds be connected (the tower ground rods 
> and the house ground rod). 

Yes, most definitley they should be tied together.  Route a bare #4 from one tower rod to your SPG, with rods every 2X rod length along the route.  Now all your grounds will be at the same potential with each other.

Presently they are not. I was told by the 
> Cel Tower installer who helped me with my tower installation that I 
> should not connect them, that the rods at the tower base would handle 
> any strike I had 

According to Polyphaser there's not enough rods to dissipate a direct strike and therefore without then some energy may tend to go towards the house.

and I might make things worse by providing another 
> path to the house by an additional ground wire between the tower and 
> house. 

I don't buy that.  Lightning wants to go to ground, in the worst way.  With the SPG there and your devices on all cables at the SPG, I wouldn't be worried.

OK experts, what's your opinion? I can do it ether way, what 
> is best? 

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