On Sun 17 May 2009 22:45:45 NZST +1200, Kerry Mayes wrote:

Not OT IMHO, although not restricted to Linux.

> I'm wanting to connect up my shed for power (3 phase),

Woow, talk about green computing! The water is for the PC cooling...? ;)

> water and data
> (phone & network).  I have (with significant help) dug the trench to
> the shed and will be organising the connections in the next few weeks.
> 
> However, if I run the network cables next to the power cables I'll
> have issues, yes?

Yes. For starters, the power cables are legally required to be in
conduit of their own, and with good reason.

You can not use garden hose as conduit underground. It is not rot
resistant in permanently damp environments. Use min 32mm PVC tubing,
pulling the 4th cable in with a pullstring will probably work if it
isn't too long or has too many bends, but anything above that and use
50mm PVC tubing. Compare effort of digging it up again with extra cost
now. Make damn sure you use the large-radius bends if you plan on
putting a pullstring in (good idea!), and be aware that what a lot of
people in trade call "large radius" most definitely isn't. As reference,
leave anything <25cm radius in the shop and don't listen to sales staff.

Shielded ducting is a dead idea. No such thing.

You will run the risk of interference issues if the power and data
conduits are too close together. I'd aim for min 10-15cm separation
(legally they may touch) for short runs, more for longer. The annoying
thing is that you won't know whether you have a problem until it's too
late and you're looking at starting over. Your only chance at shielding
is using STP instead of UTP cable. It's expensive. Shorter lengths up to
50m can be obtained cheaply as stranded with a plug on each end from the
patch cable corner, if you can handle crimping plugs for stranded cable
(don't mix them up, it won'te be reliable) and find a way to hook it up
to the patch panel. You can't crimp stranded cable into patch panel
sockets, they're always for solid core. Consider leaving the plugs on
the cable and not running it through the panel, connecting it straight
where you want it.

Putting the water between the other two *may* give you a bit of extra
shielding, and will help your separation. Putting the data conduit on
top makes it easiest to access in case you run out of space... (avoid
nots and twists at all cost when pulling the cables in), however the top
one will catch the lightning first - which probably doesn't matter
because after a hit like that you'll be looking at a lot of charcoal
anyway.

Using CAT5e instead of going straight for 6 is lousy idea and very bad
economics. If a few $100 extra pale in comparison with the money you're
spending on that shed, go for CAT7 STP.

There are cheap sources for data cabling and all that stuff. For PVC
conduit try Bunnings (I think the others didn't have all the bits), but
you really want to use someone's trade account because those electro
buggers are a serious ripoff - but talking to them nicely sometimes
makes prices reasonable.

For a laugh and some cautionary tales read
http://volker.top.geek.nz/linux/tech/outdoorwiring.html

Which reminds me, make sure your house and shed have their earths
solidly connected!

HTH,

Volker

-- 
Volker Kuhlmann                 is list0570 with the domain in header
http://volker.dnsalias.net/     Please do not CC list postings to me.

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