RE: Newbie about to run Cat5

[Robert Chasmer <robert.chasmer@xxxxxxx>]

Hawes,Timothy Edward (GEG) [mailto:haweste@xxxxxxx] wrote:
> I'm picking up a wall chaser tomorrow for my first foray into this
> Cat5 business. I'm going to be chasing walls and installing conduit
> now, but not actually pulling cables for a month or so

Don't forget you'll need some sort of vacum cleaner to suck up all the dust
as the chaser makes it.


> I was originally planning on installing 25mm round, on the basis that
> 20mm round was a bit tight for 4 cables, but am now considering
> 25mmx16mm with a snap on lid (but buried in the wall) since it's got
> more useable cross-section.

It will be easier to pull cable through if its more rounded than square,
but
if there straight runs it shouldn't matter.  I used 32mm round waste pipe
myself, I'm not sure if thats brakes some building regs though.  After
digging the walls out and installing the pipe, I re: filled the walls
leaving a depth of 5mm using 'Bonding'.  I'd not used this stuff before but
was very good.  Basically its some sort of plaster and glue mix, it dries
very very hard.  After that used lots of cheap polyfiler from Wickes to
finish the walls and allow lots of sanding.

I did this about a year ago and had have had no cracking problems even
though I've pulled lots of cables though over time.  However I did leave
the
existing TV aerial lead in the wall, and now wished I'd pulled it out.  Its
started to show through the painted wall (used to be papered), as an oily
line.


> I was planning on a 5-6mm plaster coat on top of the conduit - will
> this be thick enough to prevent cracking etc ?

As long as you can make sure there will be no movement inside you'll be ok.
plaster and filer is more likely to crack as its soft.  Bonding is hard.


> Also, in some locations, I may want to run Cat5 & speaker cable in
same
> conduit. I know mains & LV (Cat5) in the same conduit is a no-no,
but
> what about Cat5 & speaker cable ?

Hmmm, I've often wondered this.  I normally try to keep all different types
of cable seperate.  I think I've had interference between an S-Video cable
and my speaker cables before.  Probably better not to let things get to
cramped in the conduit.


> One final question. While I'm hiring the tool and making the mess,
> I'd like to put in provision for future (Cat5 based) keypads at
> light-switch height. I can chase the wall, fit the conduit and
> plaster over, but what about the backbox ?
> Ideally I'd like to fit this too, and completely hide it under the
> plaster (I'll know where it'll be when I come to use it). Is there
> a problem from the Regs.

I *always* install 45mm back boxes.  I think If I'm going to the trouble of
making a hole, fitting, filling and painting, I only want to do it once.  A
deeper box will make it easier to fit the faceplate.  The only reason I'd
not use such deep boxes was if my walls weren't made of breeze block.  I've
done some installs for mates in brick which is NOT fun.

> P.S. Any top tips for explaining to SWMBO why I need to run cable
> to _so_ many locations would be appreciated !

1) Tell her that by going to all this trouble now, you'll never have to
make a big mess and cloud of dust again.  It doesn't matter how good your
chaser is you'll still be cleaning bits of plaster of your surfaces for the
next few weeks.
2) She'll never have to see trailing cables tacked to the walls or skiring
again.
3) You can spend lots of money afterwards on gadgets to connect together
using Cat 5 etc.  Doh!!! Don't tell her that one.

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