"gibberdill" wrote in message
...
I have a new house and my main concern is not having my homeowner's
insurance nullified in the case of fire because of my ham radio setup.

I have regular coax running 100 watts through the attic.

1)Is this a violation of the National Electrical Code?

NA4G wrote:

"The National Electrical Code requires 4 inch creepage distances
and clearances between any transmitter conductor inside the building
and normal interior electrical lines. It also requires 2 foot clearance
between antennas and leadins and any other electrical lines outside.
It also requires 3 inch creepage and airgap distances beween the the
antenna and leadin lines and any building surface. The requirement
for the ``insulating support'' is nonabsorbent treated pins or brackets
with insulators having not less than 3 inch creepage and airgap distances.
(reference N.E.C. Section 810)."
( From: Robert D. Keys )
Subject: best stand offs for ladder line?




Newsgroups: rec.radio.amateur.antenna
Date: 1998/04/02 )

I may wish to go to higher power, maybe 1000 Watts and run ladder line
(450
Ohm window-line) outside the house.
3-inch standoffs outside the house are a cosmetic problem.

2) Is there a safe way to run the ladder line through portions of the
attic?
What about housing it in 1" PVC pipe and maintaining at least 4 inch
creepage distance within the attic? Is PVC prohibited in the attic?

unfortunately i don't have a copy of the code at home and don't often use it
for this type of stuff anyway. but if the creepage distance is what i seem
to remember, that is the length of the insulating standoff that is holding
the wire. so no, putting it in a 1" pipe wouldn't work, you need to have a
3" or 4" creepage length insulator.... creepage length if i remember right
is measured along the surface of the insulator, so if the surface has
grooves or ridges it is actually longer than the straight line length. hard
to explain, but it measures the length a current would travel if there was
dirt or moisture on the surface of the insulator. the requirement for a 3"
airgap would mean you need at least a 6" + wire spacing conduit with the
wire held in the center by appropriate length insulators.


3) If a 3-inch airgap distance is required between the leadin lines and
any
building surface, wouldn't that require at least a 6-inch hole in the wall
of the building to bring the line in? There must be another
explanantion...

yeah, except as noted above, if the wire spacing is 1" for the ladder line
the hole would be 7" by 6"... great fun these codes aren't they!


I'm sure this sort of thing has come up in the past!