At the moment I have some points where the cat5 cable emerges into the
same double patress box as mains electricity. Is this going to cause
me problems?

Cat5 cable should not be in the same pattress as mains electricity. Only
cables rated to 500V(?) insulation should be layed next to mains cable.
Alternatives are to separate by 50mm, or to provide extra insulation. The
last possibility might work in your case. I suspect running in plastic
conduit would provide sufficient insulation for your needs.

This is not for interference protection, but for electrical safety. I've
never found mains borne interference to be problematic with 100BaseT
ethernet, although I wouldn't be surprised if it was bad for Gigabit.

Will it really make that much difference if I clip them ever-so-gently?

Depends if you cock it up. If you hit the cable with a hammer, then you have
a substantial chance of breaking the extremely delicate conductors. An
alternative is to hit the clip in without the cable present. Then use cable
ties (mucho cheapo) to tie the entire bundle of cables to the clip.

Christian.

Martin Pentreath wrote:

Finally at the moment I have cat5 cables festooned around the cellar.
I have an itching urge to clip them to the overhead joists but I know
this is a no-no and I should be using trays. Will it really make that
much difference if I clip them ever-so-gently?

If you use loose clips (8mm) and space them fairly close
together (40cm max) they will be fine.

--
Grunff

"Martin Pentreath" wrote in message
om...
I'm in the awkward process of trying to get cat5 cable through my
victorian terrace (seems funny to be laying this stuff alongside
long-defunct gaslight piping). At least the drain rods I bought to
save being ripped off by emergency plumbers are finding a use in
pushing cable through dusty holes.

Anyway, I'm only planning on using the cable for telephony for now -
it's just that it seemed more sensible to lay cat5 just in case rather
then telephone cable. Anyway, bearing in mind that I'm not setting up
as an ISP I'm not sure how strictly I really need to follow the cat5
rules.

At the moment I have some points where the cat5 cable emerges into the
same double patress box as mains electricity. Is this going to cause
me problems? If it does will it only be a problem if I try to shove
several megabits of data down the cable, or will it interfere with
telephones too? I could put in separate patresses, but I'm fed up of
chiselling holes in the wall.

On a similar note there are places where the cable run through a void
will be very difficult unless I run it for a short distance alongside
a mains cable.

Finally at the moment I have cat5 cables festooned around the cellar.
I have an itching urge to clip them to the overhead joists but I know
this is a no-no and I should be using trays. Will it really make that
much difference if I clip them ever-so-gently?

It's been a while since I looked, but last time I checked the IEE wiring
regs prohibited running comms cable in the same trunking or channel as
mains wiring.

Double patress boxes are available with spaces for two single socket
outlet size plates and a separator between them, this would be an option
but you would need to route the cable separately.

Personally I wouldn't use CAT5 cable for telephones anyway, but that's
just me :-)

Ivor

BS 7671 'Requirements for Electrical Installations (IEE Wiring Regulations
16th Edition' prohibits circuits of different voltage bands sharing the same
enclosure, except in special circumstances.

For the purposes of the Regulations, telecommunications circuits are
generally classed as being in Voltage Band I, whilst mains voltage circuits
are classed as Voltage Band II.

If you would like further information on the ways in which you can solve
your problem and still comply with the Regulations, post back.

Cheers,

Ross

"Martin Pentreath" wrote in message
om...
I'm in the awkward process of trying to get cat5 cable through my
victorian terrace (seems funny to be laying this stuff alongside
long-defunct gaslight piping)...

Me too. :-)

At the moment I have some points where the cat5 cable emerges into the
same double patress box as mains electricity...

Personally I wouldn't do this, for safety reasons.

...On a similar note there are places where the cable run through a void
will be very difficult unless I run it for a short distance alongside
a mains cable...

I would even avoid this. I've had to reroute one such cable because of hum
(floorboards up again!).

The problem is, UK phone extensions use three wires and are therefore not
fully "balanced", which makes them susceptible to crosstalk. You can solve
this by running only two wires and fitting a "PBX master" at the end to
generate the third, but this adds extra capacitance which can affect
performance (and be detected at the exchange). Having said all that, such
effects are slight and you won't notice any problems in the majority of
installations.

Finally at the moment I have cat5 cables festooned around the cellar.
I have an itching urge to clip them to the overhead joists but I know
this is a no-no and I should be using trays. Will it really make that
much difference if I clip them ever-so-gently?

Not as long as you avoid compressing the cable. Also remember to avoid sharp
bends.

My final tip is to pull plenty of cables now so you won't have to do the job
again (even if you don't provide sockets for them all). I've pulled three
CAT5 (one for phone, one for ethernet, one spare) and TV coax to each room
in the house that might get used as a "study" and de-squeaked floorboards
while I was at it. Oh, and don't put the pattresses too close together - I
bought some brass TV and phone faceplates and found they were bigger than
the normal plastic ones and wouldn't fit!

--
Phil McKerracher
www.mckerracher.org

Thanks to everyone for the replies. I hadn't even thought of the
electrical safety angle, I was more concerned about mains hum. Just as
well I posted.

I have been using 'dual' pattress boxes from Screwfix (ref 18949)
which take two 1-gang faceplates and have a metal 'partition'
screening each half from the other. However, to make it easier to get
the cables in I've fed them both through one hole and knocked out the
partition, doh.

I guess these pattresses used properly would comply with the regs, is
that right Ross? Do you have other cunning plans which would help me
out?(Incidentally the other cables belong to a 5 amp, round-pin, mains
lighting circuit controlled from the light switch by the door and fed
from a FCU on the ring which I thought I may as well put in while I
was messing about with the floorboads).

Phil, I'm a bit worried about your reported mains hum. All the cat5
cables from the ground floor go up to the attic via a convenient shaft
I found which takes the soil stack up through the building. Between
two floors there is a length of 2.5mm T&E mains cable sharing the
shaft. I can't think of another convenient way of routing the cat5 up
through the building, so I think I'll have to risk it. If anything it
would be easier to find another route for the mains cable. All these
cables are dangling loosely in the vertical shaft, so they shouldn't
be in very close proximity. I think it's just going to be fingers
crossed (no, I can't hear a bee on the line dear).

Ivor, why wouldn't you use cat5 for telephones, am I missing
something?

And as for clipping the things the consensus seems to be that it'll be
alright if I'm very careful, so I think I'll be having another evening
in the cellar very soon.

Martin

In article , Phil McKerracher
URL:mailto
My final tip is to pull plenty of cables now so you won't have to do the job
again (even if you don't provide sockets for them all). I've pulled three
CAT5 (one for phone, one for ethernet, one spare) and TV coax

You did use EN50117 double screened co-ax didn't you Phil?

--
AJL Electronics (G6FGO) : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

In article ,
"Ivor Jones" writes:

It's been a while since I looked, but last time I checked the IEE wiring
regs prohibited running comms cable in the same trunking or channel as
mains wiring.

Double patress boxes are available with spaces for two single socket
outlet size plates and a separator between them, this would be an option
but you would need to route the cable separately.

There's a telephony regulation for telephony circuits connected
to the public telephone network which requires phone outlets to
be at least 50mm from mains outlets. Sorry I don't know the
reference for this.

Also, the separator in Double patress boxes does not seal the
two compartments if the box is recessed behind the plaster
surface any distance. (Indeed, I often end up passing earth
wires over the separator, making use of just this 'feature'.)

--
Andrew Gabriel