CAT5E shielded vs unshielded

Spinal

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Greetings! Well the time has finally come and we are going to have workers tearing apart one of our houses. I'm taking advantage of the situation to get some network cables laid through the walls, but have a query.

The cable will be Cat5e (cat6 is WAY over the top... for my wallet that is!), solid core as they won't need to move around more than what will be necessary to fit them and will all have sockets (non penetrating as its solid cable).

My query lies here, the cable will (in the most part) be laid with electrical cables. I know, not a good idea. and no, they will not be perpendicular to the electrical cables either; they will most probably be nearly perfectly parallel. So, should I go for shielded cable or does it not really make a difference?

I've found 305m of unshielded solid from eBuyer for 25£ (inc vat) but can't seem to find anything good for shielded cable. I've calculate that I will need roughly 200 meters for the entire setup, 8 single RJ45 sockets and a 8-way (or two 4-way) sockets.

Ideas?
Shielded? Unshielded? Why? Where?
Thanks!
 

marcos

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If you use normal cat5E cabling you will end up with interference. Basically the cabling will pick up a small voltage from the power cables which will cause harmonics. If you have no other alternative other than to run the cables together then I would definately suggest you use screened cabling but it is a lot more expensive, £ 35 for 305mtrs comaperd to £12 for normal.

Some people will tell you it makes little or no difference but as we recently had to rewire 6,000 + data points in a large office block in bishopsgate area recently because of this very reason I can assure you it happens.
Hope this helps

Marcos
 

Mambo

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marcos said:
If you use normal cat5E cabling you will end up with interference. Basically the cabling will pick up a small voltage from the power cables which will cause harmonics. If you have no other alternative other than to run the cables together then I would definately suggest you use screened cabling but it is a lot more expensive, £ 35 for 305mtrs comaperd to £12 for normal.

Some people will tell you it makes little or no difference but as we recently had to rewire 6,000 + data points in a large office block in bishopsgate area recently because of this very reason I can assure you it happens.
Hope this helps

Marcos
Yup, go for shielded
 
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Spinal

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Perfect, thanks! I was looking around the net, and lots of people seem to say that it doesn't matter; yet from what I studied...

Can I ask WHERE do you find shielded at that price marcos? The only place I can find shielded is maplins and they want nearly 50£ for 100 m....
Spinal
 

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This is a question, I'm not questioning your recommendations.
Why would you use stp in a fairly normal installation?
I thought (and it's been my experience) that utp is naturally resistant to EMI - twisted pair will reject common mode noise, unless you're installing it in a very noisy environment (anyone remember 20ma current loop) I would have thought it was ok. UTP is also ok up to gigabit connections.
Stp will require effective ground management (and specialised tools) - not as easy to change as utp, and is (as far as I know) much more expensive to buy & install.
As I said, I'm not questioning what you said, but I'll be getting quotes to recable our offices in the not too distant future, and I'd like to understand the advantages of one over the other - tbh, I hadn't even considered stp
 
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Spinal

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From what I know, UTP cable will pick up noise and eddy currents from being near electrical wire (which cycles at 50Hz here, so creates a nice field around it). Ideally, if you are using UTP, it should cross the electrical cables at right angles, parrallel (i.e. what I am doing) is the worst thing possible.

STP is more expensive to buy, but not that different to install. The difference is that the cable has not only 4 sets of 2 braided wires, but also a alluminium (or tin foil, or some other conductive material) wrapped around the cable. Within a hollow current carrying conductor, there is no EM field... theoretically, hence outside em fields wont interfere with your data.

That said, from what I know STP doesn't really need special tools to install, nor has a much different method of installation, but I may be WAY off.

Michele
(p.s. if I got this all correct, my supervisor would be proud of me :p)

The best price I can seem to find is ~£70 from
http://www.cableuniverse.co.uk/cata...d=1074&zenid=25cb2087e034a2035081108dc154ed08
Marcos where do you find £ 35 for 305mtrs for shielded? Thats an amazing price!
 
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marcos

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That's the price we pay Wholesale Fittings. The screened isn't listed in their catalogue but that's the price they invoice us for it. Bear in mind that on some cabling I get 98% discount. :D
 

marcos

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I'm going to get one of the lads to check to see if weve got any boxes spare. Ill let you know
 
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Spinal

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marcos said:
I'm going to get one of the lads to check to see if weve got any boxes spare. Ill let you know
<cartman voice>Schweet!</cartman voice> Thanks! If you have any, that would be great! Otherwise my bank account and maplin will have a friendly debate :)

Michele
 

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Funny you should say that :) ive just sunk another 305 metres of utp into my house bring it to 24 data points and 915 metres of cable.

never had a problem with utp unshielded close to electrical cable.
 

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