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network cabling question

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  • 03-06-2009 6:41pm
    #1
    davelerave
    Closed Accounts Posts: 1,712 ✭✭✭


    as part of our electrical installation work we drop in standard cat5e cabling for customers and we separate these from the 230v cables .are there any issues (1)with alarm companies piggybacking their wires on the network cabling and (2) crossing over and back from our 230v cables to the network cabling.im more concerned about the latter but wondered if this can cause problems later.thanks


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    #2
    Leiva
    Closed Accounts Posts: 10,117 ✭✭✭✭Leiva


    few years old but interesting reading .......

    http://forums.macrumors.com/archive/index.php/t-29136.html


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    #3
    rmacm
    Closed Accounts Posts: 2,039 ✭✭✭rmacm


    Not sure about alarm company cabling, on the electrical end of things you shouldn't run CAT5 and electrical cable in paralell....what do you mean by crossing over and back as in two conduits intersecting each other?

    If you do have to cross electrical cable with CAT5 cable you should do it as close to perpendicular as you can this should reduce interference.


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    #4
    davelerave
    Closed Accounts Posts: 1,712 ✭✭✭davelerave


    this would be in the ceiling void.we don't parallel the cat5e/mains cabling but the alarm companies pull their wires in along with the cat5e's and the mains cabling if you get me.i wondered if their crossover causes issues for the network cabling.unfortunately we're gone when this happens but i can raise the issue with the customer if neccessary


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    #5
    bushy...
    Closed Accounts Posts: 1,467 ✭✭✭bushy...


    davelerave wrote: »
    as part of our electrical installation work we drop in standard cat5e cabling for customers and we separate these from the 230v cables .are there any issues
    davelerave wrote: »
    (1)with alarm companies piggybacking their wires on the network cabling

    Just my opinion , but i'd imagine from :

    a safety point of view - alarm system goes "live" because of poor install

    network point of view - why bother installing it carefully and certifying it if some loon is injecting all sorts into it.

    They should be made pay for YOU to remove their scruffy alarm cabling after they power down the mess.

    davelerave wrote: »
    (2) crossing over and back from our 230v cables to the network cabling.im more concerned about the latter but wondered if this can cause problems later.thanks

    Would be much the same as you crossing one network cable over and back from 230 to network. I can't see any difference.


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    #6
    KeRbDoG
    Registered Users Posts: 4,261 ✭✭✭KeRbDoG


    davelerave wrote: »
    (1)with alarm companies piggybacking their wires on the network cabling

    What do you mean by piggybacking?
    Using pairs of the network cables for the sensors or just using the same cable runs as your network cabling?

    If its using the 'unused' pairs - this would be a problem in the future should the end user decide to use PoE (Power over Ethernet) to power remote network devices through your cabling or if they wanted to say use the network cabling to push video though (those HDMI->network cabling extension thingys)

    If its using the same runs, it shouldn't be a problem once they don't undo your hard work but somehow pushing the network cables beside the power cables.
    davelerave wrote: »
    (2) crossing over and back from our 230v cables to the network cabling.im more concerned about the latter but wondered if this can cause problems later

    To be honest, I've never come across any interference issues with network cabling and power cables (but power&audio cables usually = bad times) . Rule of thumb should be don't run them tight up to power cables in parallel - cable/zip ties sticking them together for long runs should be obvious to everyone as a bad idea. Try to keep them a few inches apart if possible. If this isn't possible, try to keep any parallel runs to a minimum.
    Remember, as another poster has said - the twists in the CAT5/6 cabling is there to ensure if any interference hits the wiring that the end network device can easily remove it.


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    #7
    FusionNet
    Closed Accounts Posts: 695 ✭✭✭FusionNet


    ok Im only just in from an 18 hour day so I only glanced over the reply posts.

    To answer your questions:

    1) If by piggybacking you mean running the Alarm in with the data bundles then no in theory there is nothing wrong with this. I say that in the fact that it will not effect the cat5e performance. Alarms run low voltage and these are in the trunking terms rated as "communications" cables. That can include telco which run at up to 120vdc.. The only thing that annoys me is most alarm guys are lazy and take all sorts of cable shortcuts, one namely being that bloody staple gun! Nothing more annoying than a guy putting a staple through your network.

    2) No these is no problem in crossing back. It has to be done and even in big industry 220v sockets are placed beside networks. I prefer to avoid electrical as much as possible but cat5e and cat6 are designed to deal with noise from electrical. I will warn you all now though that low voltage transformers for lights and LEDs that are on dimmer systems can cause havoc so do avoid these like the plague. A well terminated network has headrooms to allow for external noise, but ita headroom. If you certify your cabling then it will tell you if you have exceeded the limits. Exceeding the limits will cause poor network performance.

    There is specific trunking for network cables. Im not a fan of the usual 3 way conduit as its a pain to work with. The other main problem is the bends can be quite severe in them with is a big no no especially for Cat6.

    As for one of the posters mentioning that electrical and cat5e/cat6 cant be run in parellel. Im afraid thats not true. It is impossible to avoid them running along side each other in most buildings. A simple divider panel, wheater that be plastic of conduit or a divider in a cable tray makes this ok. If its a real concern you install a shielded network and bond everything. That sorts out any unwanted noise. I would recommend if running near 3 phase to use this or a fibre run.


    Anymore questions just shoot..


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    #8
    davelerave
    Closed Accounts Posts: 1,712 ✭✭✭davelerave


    thanks for all the replies .i'l start charging them a cut for piggybacking all my cable runs.seems to be lot of cowboys on the alarm side of things unfortunately


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    #9
    rmacm
    Closed Accounts Posts: 2,039 ✭✭✭rmacm


    FusionNet wrote: »
    As for one of the posters mentioning that electrical and cat5e/cat6 cant be run in parellel. Im afraid thats not true. It is impossible to avoid them running along side each other in most buildings. A simple divider panel, wheater that be plastic of conduit or a divider in a cable tray makes this ok. If its a real concern you install a shielded network and bond everything. That sorts out any unwanted noise. I would recommend if running near 3 phase to use this or a fibre run.


    Anymore questions just shoot..

    Just to be pedantic (meh I'm in one of those moods today) I said you shouldn't run electrical and CAT5/6 in paralell not can't, there's a difference :p

    And yeah a divider panel in a cable tray or a seperate conduit will make doing this ok.


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