Cable dusting next to chimney - suggestions welcome

["egelbeertje" <r_d_k@xxxxxxxxxxx>]

Hi,

because concrete walls and floors do not permit me to put cable
ducting in the walls I needed to find alternative ways to get some
bunch of cat5 from the cellar to the attick.
Now the way I've found (going via the outside of the house was no
option - swmbo did not agree to see ducting or wiring anywhere) is
passing by next to the chimney channel. (the living room fireplace
was accessible from the basement)

I've drilled some holes to find out how the chimney construction was
build and actually it's a tube within a tube with thermal insulation
between the inner fire proof stone tube and the outer plain concrete
building blocks.

Assuming the insulation is fireproof......I was able to put some
1inch plastic pipes between the layer of insulation and the inner
tube/smoke channel. (actually hammering them up the chimney channel
until the whole 3 meter tube was gone, then crawling through the
attick to find the hole in the chimney and prying the tube from
behind the insulation - it was a fun day's work to get the 3 tubes
in , and I need to put 3 more...pffff)

Now the plastic tubing is normal electricity fire retarding plastic
but what other means of preventing these plastic tubes from melting
and melting the cat5 could I take ??

there is no fireplace in place yet so it's not an immediate concern
but once we will install a gas powered fireplace, it may be an issue
of heat production.

main question after all this, how hot will the chimney channel become
once the fire is on?

suggestions welcome.....wireless is not an option.

rgds Rob.