On 10/15/2020 6:05 AM, jimlux wrote:
Most coax has a 300V rated jacket (9913 is 300V, for instance, as is
9258 (RG-8X), LMR-400's datasheet doesn't even give a UL rating)
UL ratings for cable are for flammability, flame spread, and noxious
fumes when they burn. They are the result of the real life event upon
which "The Flaming Tower" movie was based, when excessive neutral
current that resulted from triplen harmonics in vertical cable runs
spread through the high rise building.
Romex (NM-B) is 600V, as is the usual THHN building wire.
There's some trickyness with respect to the code in running different
voltages. It's not clear that antenna cables are Class 2 wiring - the
rule says that Class 1 and Class 2 can't run in the same conduit, unless
separated by a continuous barrier (is a second layer of insulation, e.g.
Romex, a "continuous barrier"?)
While single phase mains power is nominally 120/240VAC, capacitors for
use on mains power wiring must be rated for 3kV/6kV, depending on how
they are connected, to withstand voltage transients that result from
equipment connecting and disconnecting, and from lightning. It's not the
operating voltages, it's the abnormal voltages.
It's been a while since I read the code, but I've specified conduit
systems for many sound systems in large and small buildings. Antenna
cables are LV wiring, as are audio, video, and most other wiring for
small signal circuits. In buildings, LV wiring must be separated from
mains power wiring, either by a suitable barrier (as in a cable tray),
or in separate conduit.
73, Jim K9YC
725-54(a)(1) lets you put low voltage and high voltage in the same
enclosure where the HV is not more than 150 V to ground and "solely to
connect to equipment".
The
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