On Jul 23, 8:48*am, "Szczepan Bialek" wrote:
*"Jim Lux" ...



IIRC the purpose is to primarily drain off the static charges so the
gnd-cloud potential difference is minimized. A direct strike will usually
just melt whole house wiring, etc. etc.

Not true.

The cloud has SO MUCH charge you don't stand a chance of bleeding it off.

Each cloud has a charge and the all is flowing to the ground. But only 20%
as the direct stroke.

The rule is simple. A mast with the polished ball on the tip attract the
direct stroke (polished ball do not dissipate).
A mast with many sharp spikes dissipate the static charge and eliminate the
direct strike.

wrong, sharp spikes are designed to start an upward streamer that
connects the downward leader to the lightning rod. that is why they
have a sharp point, to reach the breakdown field gradient before
anything else around them.



Direct strikes are typically around 20 kA, and can be as high as 100kA.
Both can be adequately carried by the usual AWG6 wire, because the current
pulse only lasts a few microseconds.

It is the oscillating current which has a canal in the air. It is not
obliged to flow only in the wire.
S*

normally they don't oscillate, it is a mono-polarity pulse.