On Fri, 30 Sep 2011 11:36:06 -0400, "Percival P. Cassidy"
wrote:
On 09/30/11 11:23 am, RicodJour wrote:
I am running network cables -- shielded, if that makes a difference --
above suspended ceiling where there is already 120V Romex wiring in
places. This 120V wiring is stapled to the joists at intervals.
Is it OK for the network cables to lie on the ceiling support members,
and thus beneath the Romex? Or should the network cables be above the
Romex? Or should one or both be in conduit? -- more precisely, should
what is now Romex be redone with individual conductors in conduit?
no issue even with cat5 or cat5e non sheilded - as long as your space
above the ceiling is not an air plenum - and then you just need plenum
rated cat5
What's the reasoning behind plenum rating a computer cable? Is there
some fire-reasoning behind it or what? What's the difference between
rated and non-rated cable?
Fire rating. Plenum cable will not support combustion when flame is
removed - will not flame on it's own - and different smoke. Non-plenum
rated is not allowed in an air return.
Yes, but my question was whether the OP's above-ceiling space is
actually a plenum. I had assumed the question was residential, a
basement and the space was not used for airflow. Granted, that's
reading a lot into it, but perhaps they were bad assumptions.
Here are some interesting (but boring!) videos of the different cable
ratings burning.
http://www.l-com.com/multimedia/vide....aspx?ID=13100
Quite a difference between plain vanilla PVC and rated cable.
You are correct: this is a residential setting, with a suspended ceiling
installed in the basement.
Perce
But we still don't know how the cold air returns work. If the cold air
return just dumps into the ceiling, and the ceiling is open to the
furnace room - and the furnace drawr return air from the furnace room
- it's a plenum. Ditto if the cold air return had an opening into the
basement, which is now semi-blocked by the dropped ceiling, so it is
drawing return air from above the ceiling. Neither is a proper approch
- but I've seen stranger!!!