Cable (plenum) questions

[John]

My brother and I are installing a DVR-based security system into his
pizzeria. We've got two 60' runs that need to be made out to the two outside
cameras to cover dumpsters and rear parking area. We will be running the
coax and power cables up into a drop ceiling, then 12' over the ceiling,
then out and up to the roof. We do have a/c ducts in the drop ceiling but
they're enclosed. The reason I mention this is because I'm not sure if the
space above the drop ceiling is considered a plenum. Is it, and if so would
we need to run plenum-rated coax -and- power cord? ? Thank you.

 

[Matt Ion]

My brother and I are installing a DVR-based security system into his
pizzeria. We've got two 60' runs that need to be made out to the two outside
cameras to cover dumpsters and rear parking area. We will be running the
coax and power cables up into a drop ceiling, then 12' over the ceiling,
then out and up to the roof. We do have a/c ducts in the drop ceiling but
they're enclosed. The reason I mention this is because I'm not sure if the
space above the drop ceiling is considered a plenum. Is it, and if so would
we need to run plenum-rated coax -and- power cord? ? Thank you.

Probably be best to check with your local building inspector or city planning
department if you really want to be sure - different jurisdictions have
different codes for how long unshielded non-plenum cable runs can be (in
Vancouver proper, for example, I think you're allowed up to 9 meters before it
either needs to be FT-6, or enclosed in conduit; different suburbs have
different specs).

Whether or not the area is even considered plenum space depends on whether there
are separate air-RETURN ducts; if there are, you're likely safe anyway. This is
another area the city planning department could be useful, as they should have
the building plans on file and can tell you what the requirements are.

Ultimately, you're probably fine with FT-4 cabling anyway, unless you're doing
major construction requiring an electrical inspection. If there are no big
renos and no permits involved, then nobody's going to care whether your cable is
plenum-rated or not.

Some additional reading: http://en.wikipedia.org/wiki/Plenum_cable