On 6/4/2013 1:24 PM, Jon Elson wrote:
bud-- wrote:


The way it is done is all wires - power, cable, phone, antenna, dish -
enter at about same location. Entry protectors for the signal wires
connect with a short wire to the power earthing system.

Well, if you do this, you probably end up destroying everything in
the house, including the wall outlets and Romex in the walls. I have
heard of people having this happen, where all the Romex was just
empty plastic tubes with burn holes every couple inches where the
copper vapor escaped. All the wall outlets were blown out of the
wall boxes and reduces to fragments. Having to run new Romex inside
all the interior walls runs something like $50K now.

It is, essentially, how hams protect high antennas that are likely to
get hit. The intersystem bonding is heavier and the earthing hams have
is much more extensive.

An electrical inspector in another forum has a weather station that is
on a metal post with the post tied to the power earthing system It has
been hit twice. Minimal damage on the first hit and with fairly minor
added protection he had no damage on the second hit. The weather system
has a data lead that comes down the pole.


My idea, which doesn't meet code, is to try to draw the main currents
AWAY from the rest of the house and possibly preserve some of the
appliances. Whatever is connected to the antenna will be complete
toast either way, but isolation may help some of the appliances
survive.

Jon


If you want to protect from a direct lightning strike install lightning
rods. Lightning rod protection is more complicated than you antenna
earthing scheme and your antenna will not substitute for a lightning
rod. Side flashes into the house are likely. And damage is much more
likely from power service surges and near strikes. Lightning rod systems
are required to be bonded to the power earthing system.