Re: Short Plenum Run Question

[robertlbass@xxxxxxxxxxx]

Please DO NOT run any cables inside air ducts except those which are
required for the operation of the ducts themselves.  An example of an
acceptable cable would be one used to power a damper.  No other cables,
including plenum rated cables, are permitted in the air ducts.

Plenum cable is permitted in a plenum air return, but that is not a
duct.  Plenum spaces are sometimes found above the ceiling in
commercial office buildings.  Instead of running a complete system of
return ducts, grates are installed in the ceiling and room air passes
though them on its way back to the furnace or A/C unit.  Because these
spaces are the only place wires can be run in such structures, you are
allowed to use plenum cable in them.  The interior of an air duct is
not considered a plenum for running cables.  Significantly stricter
rules apply.

Besides the fact that it's a code violation to run your alarm,
automation or structured wiring system cables in air ducts, it is also
a life safety hazard.  Perhaps I should say that the other way around.
Because it's a life safety hazard, it's against code.  Either way,
please don't do it.

Regards,
Robert L Bass
www.BassBurglarAlarms.com