[TowerTalk] Sparky Pays a Visit

[Tom Rauch]

> OK - Question.  My aluminum entrance panel is in a
second-floor
> window.  The hardline (CATV) comes out of the ground
(conduit) alongside
> the house, and flexible coax runs from there across a
porch roof, maybe 50
> feet to the shack window.  Where the hardline comes out of
the conduit, I
> have grounded the shield to the same ground rod as the AC
service.

Is that metal conduit Pete?


> I disconnect everything at the entry panel but don't
usually disconnect
> equipment from the house AC.  With close hits I have had
three instances
> when I have had arcs from the center conductor of the
barrels in the entry
> panel to the shell, and thence to ground -- it's pretty
startling, but
> aside from a little soot, no visible damage.


I don't think intentionally grounding the centers will make
much difference.

The big issue is distance to earthing from the upper panel.
I don't think you'll ever get a low impedance ground path
from there compared to the path through house wiring.

If it was my installation, I'd have the entrance panel
downstairs and disconnect there. Maybe I'd have two of them,
the upper one inside the room and tied into the power mains
and ground buss at the operating position only. I'd just be
sure the bottom one was very well grounded to the service
ground and as good an earthing system as possible.  I'd
disconnect at the bottom or at the entrance to the room
before reaching the upper ground plate.

The important thing is to make sure the cables coming up the
wall are tied to the power mains with a very low impedance.
That way you don't have a large potential difference between
the cables and the wiring in the house.

How good is your ground system and how far away are the
towers?