It is a long time since I last posted on this forum but I have a
I need to bury a mains power cable about 25 Metres in length to my
workshop at the bottom of my garden.
At the same time I need to have a Broadband cable to the same
My question is this, will it have an adverse effect on the Broadband
signal if the 2 cables are buried in the same conduit?
The mains power cable will cary only the same as the house circuitry
On Mon, 18 Jun 2007 19:06:31 +0100, Dave Plowman (News) wrote:
I don't think so. A quick search found a Belden CAT5e cable with a rating
of 48Vrms (RS 331-8663).
Personally I'd not run the xDSL signal any further than it absolutely has
to. Fit the DSL modem at the NTE and run network cabling to your
switch/firewall or WHY.
If you want BB in your garden workshop either run a network cable or two
(phone as well?) in a separate conduit(*) or use one of the network over
mains devices previously mentioned.
(*) The mains really ought to (must?) be run is SWA and that can be
directly buried in sand in a trench so only a conduiut for the LV stuff is
Dave. pam is missing e-mail
That probably just relates to the inter conductor insulation. Although
that too looks pretty chunky. But I was referring to the outer insulation
which would be the requirement if alongside a mains cable. Personally I'd
be happy to tape it to SWA. ;-)
*What was the best thing before sliced bread? *
Dave Plowman email@example.com London SW
On Mon, 18 Jun 2007 22:50:00 +0100, Dave Plowman (News) wrote:
I don't know what Cat5 cable you have looked at but the insulation around
a conductor on normal mains cable is at least twice, probably nearer 4
times as thick as that around a Cat5 core. Similary the outer jacket of
Cat5 is thinner than that on a mains cable.
Dave. pam is missing e-mail
Why do you say that?
The DSL might have come many kilometres from the exchange in an un-screened
with hundreds of other pairs and running close to many sources of electrical
Why do you suppose that an extra 25 meters is going to be detrimental?
Contrast this with the known distance limitations of 100Mb and Gigabit
Experience. I've had different preformance from my ADSL after simply
moving the wires around in the junction box and NTE. We are talking very
low levels of RF at the upper end of the DSL range, small changes can make
As a balanced pair with other balanced pairs, mutual interference is quite
low. Induced interference is common mode and should be rejected by the
modem. if it's any good.
The DSL signal is "delicate" and easily interfered with, no point in
opening any more windows for interference than absolutly neccessary. Where
are there more tiny arcs, switching transients etc In the home or under
Proper networking kit is designed to be robust and can be run almost
anywhere without much regard to noise sources.
Dave. pam is missing e-mail
I apologise for my ignorance but I am now thoroughly confused.
All the discussion about cable resistances etc. mean absolutely
nothing to me but I am pleased that it has stimulated a debate about
Taking this thread to its ultimate: Do you suggest that running both
cables side by side or even taped together as one poster suggested, is
the way to go, or should I still consider seperate conduit?
I really appreciate the response,
On Tue, 19 Jun 2007 07:46:04 UTC, " firstname.lastname@example.org"
1) No guarantee that the cable insulation is suffcient for the reg; I
doubt it. And if there were a problem, all your DSL kit would experience
mains voltages - and so might you.
2) There may be interference, there may not. Why take the risk?
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
It may, it is contrary to how it is supposed to be done, but in reality
will usually work without difficulty. You could also use "home plug"
devices to do away with the data wire and route the network over the
How does those network systems avoid sending the data down the 'ring
main' in the street, is their something about elecy meters that
prevent such transmitting of data or does it work by encrypting the
data like (a correctly set up) wireless system?
The Homeplug devices I bought use encryption (DES I think) so they should be
fairly secure. They were very easy to set-up and are completely transparent
when in operation - manufacturers of other networking kit could learn a
lesson here. I used the Homeplug gear to replace a Cat5 cable running
between a house and a barn, removing any earthing/lightning/mice issues
related to the Cat5.
They claim to not get out of the property past the meter, but I am not
sure if there is any technical reason for this, or if it just comes down
to range. They do have encryption, and you can group a number of them
into a private network.
My thanks to everyone who has responded.
It appears that laying 2 separate cables that are at least 50mm apart
min. is the way to go.
I did a Google search on "Homeplugs" and since it appears that 2 plugs
are needed the expense is getting prohibitive and the security issues
are not very tidy.
My thanks again for your assistance,
If it were my shed;)
I have my broadband come in to the gaff then to the modem/router that
goes to wherever I want via CAT5, which is very robust and noise immune.
The mains cable goes via a lump of direct bury SWA, the other cables go
in some 50 mm ducting that we got from a builders merchants c/w a phone
line and an intercom and front door bell, and CCTV signal via an RF
If their all in the same duct it wouldn't bother me technically at all
re insulation and mutual coupling. In fact in an older property there is
a cat 5 cable buried underground by itself thats still in fine condition
having been there 8 odd years now!.
I'd not bother with the "plugs" for this at all, CAT 5 wired is a much
I'd have thought that the current-measuring bit of the meter would
have had sufficient inductance to effectively block most of the RF
applied to the line downstream of it.
If you have a section of SWA there's likely enough capacitance between
the conductors and the armour wires to limit the performance at RF.
You really have to take an entirely RF-based (capacitance/inductance)
assessment of your installation as well as the power-based stuff.
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