In a message dated 99-08-26 20:44:28 EDT, you write:
> 1. The photo just shows some "test" scenarios, if you will. I want to
> decide the main physical connections to the tower for grounding.
> 2. The solid copper is #6 attached to a BRASS block bolted with a
> STAINLESS bolt to an ALUMINUM angle adapter that I got at an electrical
> supply house here. It turns out that I wasn't trying to use the ones
> from Champion correctly - They WILL attach to the tower, but they're
> really way too big, and I think the smaller ALUMINUM one pictures will
> work out better for me. Doesn't look like either one will help attach
> the copper strap. If I go this route, I would use #4 or #2 wire. Is
> insulated OK or not?
Hi, John --
Finally had a chance to get caught up on my email.
Insulated wire? Bare wire is what's used in commercial installations.
Anywhere the wire is in the dirt should be in direct contact with earth so
bare wire is the way to go.
Glad that you got the angle clamps figured out. I guess we need a photo
of how they work on the website.
You're mixing up several dissimilar metals but as long as you use an
antioxidant on all connections, it won't hurt you.
> 3. You can see that I tried attaching copper strap to a small SS bolt
> that bolts into the STEEL boot at the bottom of the tower - This doesn't
> seem great to me either, but do you think this is any better than using
> the #2 or #4 wire to the angle adapter??
The wire is fine; strap is used mostly in rocky soil.
Attaching the strap directly to the tower leg is fine - use a big
washer over it and a good antioxidant on all contact points.
You could use BOTH methods, you know. It's not an 'either-or'
> 4. The other thing a friend suggested, is to drill a big hole in 3 inch
> strap and put it over the BIG base lug/bolt that's in the concrete -
> then run to the rod(s). Maybe better than #3 above?
It's the same thing. In all of these scenarios, you're connecting the
tower to ground.
> 5. Does it do any good/harm to use NOALOX on copper-copper or
> copper-steel, or is it only useful when one surface is ALUMINUM?
Use an antioxidant on ALL mechanical ground connections.
> 6. And, FINALLY, would you attach the conductors for each leg near the
> bottom or each and run flat across the concrete to the rod, or would you
> attach the conductor up higher, e.g. 4 feet up the tower, so that the
> conductor would sweep towards the ground rod with less of a sharp angle?
Up higher. You don't want any sharp angles - they are higher
inductance points and negate the low resistance path to ground. Gradual
sweeps are the way to go. You're trying to make it easy for lightning charges
to find a path to ground don't forget.
You want to have multiple ground rods off each leg as well. Roger
Block's grounding book has *some* helpful information but is pricey for what
you get. I've got a reprint of an article he wrote for ham installations
that's available for an SASE to Box 572, Woodinville, WA, 98072, that
includes the meat of the information.
Cheers & GL, Steve K7LXC
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com