So a lightning bolt comes down through two miles of AIR (which is an
insulator), but it won't jump a gap .010" between the sliders on the tower legs?
Also, aren't crank up towers Ufer grounded by default, since the anchor bolts
go a decent depth into the concrete?
Chris
KF7P
On Oct 24, 2017, at 11:39 AM, Don W7WLL wrote:
> That was the question I have Steve and I don't truly think it is a non-issue,
> particularly with the crankup tower instructions I've read re lightning
> protection.
>
> My interest was piqued by the discussion of the requirement to ground all
> cable legs, the number of ground rods to use, wire/strap size, etc. This is
> just not feasible that I can see with a crankup so was interested in best
> approach. Should I have more ground rods. If so, how should they be placed or
> spread? Should I depend on a single base ear tower ground where that ear is
> attached to the tower ear by just the pressure of the galvanized bolt
> fastening? We suffer a lot of salt buildup on everything and depend of course
> on anti-seize to ensure the bolts can be later separated. I see no way to
> utilize the solutions suggested for fixed rigid towers such as the hefty and
> costly clamps to crankups.
>
> So, is the cable system within the crankup tower sufficient for a lightning
> strike? The cables are well lubed (I live on the ocean and use the lube and
> lube process recommended by the local marine cable rigger who installs tons
> of rope cable on the fishing and crabbing fleet). As well, the cables are
> connected only by contact to the pulley wheels and the thimble contact at the
> ends.
>
> Yes, the tower sections certainly touch in some way but my inner tower
> section facings are lubricated, so am unsure just how robust the contact area
> is.
>
> Summary - just wondered what others did with their crankups re creating a
> grounding system as robust as those that have been discussed for fixed towers
> (or can you?).
>
> Don W7WLL
>
>
>
>
> -----Original Message----- From: k7lxc--- via TowerTalk
> Sent: Tuesday, October 24, 2017 8:11 AM
> To: patrick_g@windstream.net ; towertalk@contesting.com
> Subject: Re: [TowerTalk] height of ground rod at tower base
>
>> 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.
>
> Isn't the tower already continuously conductive? What about the cables
> that connect each section? Isn't this a non-issue?
>
> Cheers,
> Steve K7LXC
> TOWER TECH
>
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