[TowerTalk] height of ground rod at tower base

[Patrick Greenlee]

The movable sections of a crank-up tower are never so perfectly balanced 
that they don't touch each other.  I suppose you could connect a wire 
from each section to the one below such that it reaches from clamp to 
clamp when the tower is fully raised and "bulges outward" in a non 
interfering manner when the tower is lowered.

I am not one of the most experienced tower guys here but I have never 
seen a tower so connected and personally don't think it is a realistic 
requirement but will suspend judgment until the "big guns" hereabouts 
have ruled.

Patrick        NJ5G

On 10/24/2017 12:48 AM, Don W7WLL wrote:

> All this discussion has been centered around standard tower. It is not 
> possible to attach a ground clamp or similar connection to each leg of 
> the moving sections of crankups such as the HG-70HD. Probably true for 
> some other crankups too. The only ground connection on the HG-70HD is 
> made at the rear base ear (opposite the hinge side). It would be 
> possible to get a ground from the rear base ear to the lower fixed 
> section lower cross panel - if you drill a hole in it.
>
> In my case, a grounding wire goes from the base ear to a 8 foot ground 
> rod (one). The tower fixed bottom section is secured to the base ears 
> to the crankup tower lower section by nine large galvanized bolts .
>
> The HyGain installation manual goes no farther then addressing 
> lightning protection than saying to right a ground wire from the 
> single base ear to a 4 to 8 foot ground rod and use a coaxial 
> lightning arrestor at the house. I looked at the 25 page document done 
> to satisfy the LA code dept, done by a CA PE, and it does not address 
> lightning protection or grounding at all.  I would imagine the 
> raising/lowering cables may be the best moving sections electrical 
> connection, excluding the coax.
>
> How have others assured a good solid path between all sections of 
> crankups short of the coax itself??
>
> Don W7WLL
>
> -----Original Message----- From: Paul Christensen
> Sent: Monday, October 23, 2017 8:51 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] height of ground rod at tower base
>
> Jeff,
>
> Here's a link to a Seapac presentation on NEC Article 810 and amateur 
> radio.
> Start around p. 26.
>
> https://www.seapac.org/documents/seminars/2013/2013-Kuhlman-Applying%20the%2 
>
> 0NEC%20to%20Amateur%20Radio.pdf
>
> In my case, the inspector wanted the tower base installed exactly as 
> shown
> by my P.E. at the time I applied for the construction permits. The P.E.
> copied the Pirod grounding plans in their entirety.  That meant three 
> 8 ft.
> ground rods, placed at the foot of each tower leg and connected with 
> #2 soft
> copper wire to a ground rod+clamp.  Your inspector should have no 
> issue with
> a buried ground rod provided the clamp is meant for burial, or it's
> exothermically welded.
>
> That said, to pass inspection, the tower ground was installed as per the
> P.E., which followed Pirod.  I kept the ground rod end visible for the
> inspection.  I didn't care because in three weeks, it will all be 
> ripped up
> and started over with a Motorola R56 system.
>
> The inspector was deeply concerned that I installed a Ufer ground in the
> self-supporting tower piers when not specified by the P.E.  I was 
> gulping at
> the thought of a P.E. redraft of the documentation, but it wasn't needed.
> After a lengthy discussion and on-site review of printed Ufer 
> literature, he
> begrudgingly approved it.
>
> Paul, W9AC
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of 
> Jeff
> Sent: Monday, October 23, 2017 10:00 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] height of ground rod at tower base
>
> What does the NEC code (meaning a safety ground and not the more 
> expansive
> proper lightning dissipation) for minimal grounding of a tower?
>
> I need to get the rural county building inspectors out to look at my 
> towers
> and want to show them something that they will have seen before with 
> respect
> to a basic safety ground.  From what I understand locally that means a 
> pair
> of ground rods in a configuration like what would be required at a 
> house for
> the mains entry.
>
> To that end I am unsure what the height of the ground rod should be in 
> the
> NEC context?  Is the connection wire/rod joint to be made above grade, 
> even
> with grade or below grade?
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
>
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