Installing Cat 5 cables next to power cables, shielded or unshielded?

Discussion in 'Mac Help/Tips' started by amnesiac1984, Jun 10, 2003.

  1. amnesiac1984 macrumors 6502a

    Jun 9, 2002
    Hi all.

    We're building a new house and its my task to sort out the housewide network. We want to eventually use gigabit but 10/100 will be fine at the moment. basically I'm at the cable planning and routing stage. We are currently laying floor insulation and our electrician is putting down power cables for fittings and lights and appliances etc. We have left channels in the floor for these cables and I want to lay the Cat5 cables for the network alongside. basically am I going to need to get shielded cables or not? The shielded ones are more expensive obviously. What do you all you gurus reckon?

    Cheers in advance

  2. dotcomlarry macrumors regular

    Jul 16, 2002
    Akron, PA
  3. Macmaniac macrumors 68040


    Definantly go for shielded, electrical wiring can cause interference with networks epescially if the power cable is close to the network cable. If you can avoid it keep them seperate and you won't experience interference.
  4. saabmp3 macrumors 6502a

    Jul 22, 2002
    Tacoma, WA
    Noooooo, don't use Cat 6. Especially if your going to put them around power cables. Cat 6 is basically notorious for it's horrible interference effects. If you want to use gigabit, then Cat 5e is plenty for what you are going to be doing. Anyways, after gigabit, were probably going to have to upgrade to optics anyways to get considerably faster network.

  5. patrick0brien macrumors 68040


    Oct 24, 2002
    The West Loop

    The very nature of twisted pair wiring - which 8-conductor Cat5 (5e) is, is to eliminate crosstalk. However, if you are in proximity of an AC current, you will definitely need sheilding.

    Rule of thumb, if there is any doubt, shield.

    I just did this same thing to my house, and I'm glad I did.
  6. tcolling macrumors member

    Dec 19, 2001
    watch out for bad advice

    you may be getting some bad advice here, maybe not. I'm in the States, where unshielded cable is the norm. Seldom is shielded used. I work for a company that designs and installs network systems, soup to nuts. Only one customer has ever requested shielded cable, and we have NEVER recommended it at the cat 5/5e level.

    The problem is, if the shield is not terminated properly, it becomes an antenna. I'm not saying don't use it, just make sure that you have it terminated properly if you do.

    Much more important is to use good cabling practices, i.e. NEVER run data cable next to power cable, unless one of them is separated by an metallic enclosure such as conduit, or a power pole with separate chambers. Stay at least 12" away, and you should be fine. Cross power cables as close to perpendicular as possible. Avoid microbends (little kinks in the cable as you're pulling), and don't pull too hard during the install.
  7. amnesiac1984 thread starter macrumors 6502a

    Jun 9, 2002
    Re: watch out for bad advice

    So you are aying don't go near them, well we may have to. So are shielded worth it if we can't avoid powercables? What do you mean by terminated? Surely the shielding is just a metal barrier and works the same way as a an external one between the powercable and the cat5 cable, so why do you have to terminate it?

    Whats the difference in cat5 and cat5e, what do cat 6 and 7 do? This is just a simple home network for macs and the occasional visiting PC but we want to be futureproof. Is it worth laying some pipes or something so we can put new cables in when the standards are all changed?

    I've ethernet for years and up until recently we had a 10 base T bnc coaxial network until i got my powermac, and I understand its capable of gigabit so that would be worht it as most new macs we may buy will also have that.

    Anway, thanks all you guys, if your interested (i posted this before) here are some pics of the new house.
  8. tcolling macrumors member

    Dec 19, 2001
    shielded clarification

    Here's a little clarification...

    When using cat 5 shielded, the shield needs to have its integrity preserved throughout the system. In other words, the NIC has to support it (I'm not sure the macs do), the jacks needed to be shielded jacks, and the patch cords need to be shielded. If this is not done, you will have problems.

    I guess I'm not sure why in a new construction you can't keep the data lines at least a foot away from the power. You can come near, and even cross the power, as long as its perpendicular or for very short distances. I still recommend unshielded, that is what I ran in my house. (After four years, I haven't even terminated it yet, I haven't needed to network yet). Gigabit ethernet runs fine on cat 5e, some older cat 5 may have problems, but I doubt any new cable would. If you aren't aware, the difference is that 10Meg uses two pair, Gig uses all four. Don't bother using cat 6 or 7, they're tougher to terminate and won't give you any useful benefits. I can't imagine a home network even needing anything close to gigabit speeds anyway. As I mentioned, our company of about 30 employees that designs network systems, wiring and electronics, is running on 10/100 equipment. You will never outgrow cat 5e wiring in a home, and even if you do, it will probably be replaced by wireless someday anyway.
  9. yzedf macrumors 65816


    Nov 1, 2002
    cat 5e run through your normal sized conduit (metal pipe) will be fine. gives you easy way to add more cable in the future if necessary.
  10. amnesiac1984 thread starter macrumors 6502a

    Jun 9, 2002
    Re: shielded clarification

    Thanks that is very useful. We do use the network a lot, and Dad runs his business from home, iTunes is streamed and I often backup about 100gb to a firewire drive on my Dad's TiBook so speed is always useful. We can run the cables somewhere compeltely different but it woul dbe nice to have it in the same trenches as the powercables which are going in now. We have two layers of kingspan 3/4 inch foam insulation that I'm putting in under the floors and above the concrete on the ground floor. We have left trenches approx 6" wide to put all the power cables in. These trenches will be accessible after the floor ahs been laid. I can probably get away with not going anywhere near them if I'm clever but its nice to know all the fact before designing the network.

    Again thankyou very much this has been most useful, and thankyou all the other guys.

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