[TowerTalk] FW: Tower Grounds

[jimlux]

  I
> heard that lightning does not like to take sharp turns, hence, the arc 
> of copper and not bolting to the leg bolt.


Lightning doesn't care - the inductance of a gentle bend or a sharp 90 
degree corner or a 45 degree "cut the diagonal" is basically the same - 
until you start getting a complete turn or more, inductance is all about 
the length of the conductor.

The rationale behind the "no sharp bends" dictum is to reduce the 
incidence of flashover from the lightning conductor to neighboring 
stuff. This is a big deal if you're running a downlead from a lightning 
rod (air terminal) next to a metal downspout, for instance.  You don't 
want lightning flashing over from the downlead to pipes inside the wall 
or anything else.

The sharp bend has a smaller radius of curvature, so the breakdown 
voltage to adjacent objects is less.

Remember that parallel currents cause conductors to be forced together. 
So your conductor that is bowed out and away, and basically in parallel 
with the current carried through the base and concrete, is going to be 
pulled in towards the tower to try and minimize the gap.