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@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@contesting.com] On Behalf Of Jeff
Sent: Monday, October 23, 2017 10:00 PM
To: towertalk@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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