Pink Cbus Cable

Discussion in 'C-Bus Wired Hardware' started by DDirk, Dec 11, 2009.

  1. DDirk

    DDirk

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    Can anyone please confirm if the Pink Cbus cat5 cable can be use in conduit underground or will this effect comms if moisture was to seeps?

    Or do I not use the Pink cat5 and use the jellyfill cat5?



    Thank you.

    DDirk
     
    DDirk, Dec 11, 2009
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  2. DDirk

    znelbok

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    well if moisture did get in I would expect problems.

    I have run both underground. One run of pink has been in for about 7 years with no problems, but some other cat5 with it has failed.

    I then decided to use jell filled for every other run that went underground (there are about 4 underground runs at my place).

    The problem with underground runs is that if it fails, you need to pull it out and that may not be easy or even possible, so do it right the first time and make sure of it - use the jell filled cat6 cable.

    Mick
     
    znelbok, Dec 11, 2009
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  3. DDirk

    DDirk

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    Pink Cat5

    Thank you for your post Mick.

    I just was not sure how good the pink cable was.

    I think most people would use the same cable indoor
    and underground but I also think its best to go jelly.

    DDirk
     
    DDirk, Dec 13, 2009
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  4. DDirk

    Darpa

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    The primary reason for the pink c-bus cat5 is that the outer sheath is rated to be run next to mains wiring. So it can safely be run inside a switchboard/DIN enclosure safely. As long as the underground conduit doesnt have any mains cables inside it as well, then there is no reason at all you cant run Gel-filled cat5/6.
     
    Darpa, Dec 13, 2009
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  5. DDirk

    Aaron

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    I thought all Cat5e cable manufactured in the last two-three years was meant to have mains rated outer sheath?:confused:
     
    Aaron, Dec 13, 2009
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  6. DDirk

    ashleigh Moderator

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    Sadly, no. Most cat5 has an outer sheath rated to 500V or 1000V.

    In order to run alongside mains it needs to be rated to 3750V.
     
    ashleigh, Dec 14, 2009
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  7. DDirk

    cbuster

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    That figure doesn't make sense, are you sure ?

    Most cables rated for running along 240v lines need only be 600 - 1000V?
     
    cbuster, Dec 14, 2009
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  8. DDirk

    Conformist

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    Yes, this is correct. 3.75kV insulation is required for mains insulation however, you must still observe general segregation rules. You should not run this cable along side, mains (240V) cable due to the risk of induced voltages (even with twists in the cat5e). It is (the insulation ) more for taking the cable into mains enclosures such as electrical switchboards.
     
    Conformist, Dec 14, 2009
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  9. DDirk

    ashleigh Moderator

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    Common misconception that a rating > 240V is good enough.

    The wiring rules require an insulation breakdown rating of >3750V when running SELV alongside mains IN AN ELECTRICAL DISTRIBUTION BOARD.

    This means you can use a lesser standard (and off the top of my head w/o the rules in front of me) when outside the electrical distribution board. So for example, outside the board you can use plain ole Cat5 and it would be OK. But inside the board it must be rated to 3750V, there must be double insulation, segregation, yada yada.

    Long runs of Cat5 - whether for your ethernet, cbus, or anything else, should still not be laid alongside mains to reduce the risk of induced currents (as above). That's just a normal good practices wiring rule.

    When you go inside the electrical distribution board, you have no choice: mains and SELV [safety extra low voltage] ARE in the same zone, and HAVE the potential to come in contact. Hence the insulation requirements, hence the higher standard.

    The other reason for the higher standard is a risk / zoning thing. The requirement is for 3750V isolation inside the cabinet, on the grounds that you are closer (higher available current path) for surges, lightning strikes and so on. Outside the cabinet the reasoning goes that risks and the induced voltages from surges, etc, is lower - hence a lower requirement.

    In answer to the next obvious question: "So who makes up these rules" - it depends. National codes are different. The above applies commonly through Australia and Europe, but you should check national wiring codes.
     
    Last edited by a moderator: Dec 14, 2009
    ashleigh, Dec 14, 2009
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  10. DDirk

    cbuster

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    You're probably right about the 3750V insulation for DISTRIBUTION BOARDS.

    We mainly work with electrical control cubicles that are physically outside the main ELECTRICAL DISTRIBUTION BOARDs - but these cabinets can be rated at anything from 10A to 500A which contain there own sub-distribution circuits, and it is quite common to run low voltage control signals (eg PLC's Drives, sendor transducers and electronic amplifiers) with cables rated at 600-1000V ?
     
    cbuster, Dec 14, 2009
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  11. DDirk

    NickD Moderator

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    The issue here is that the 3750V isolation is required to maintain the SELV rating *of C-Bus*.

    I don't know about these other types of signals that you are referring to, however I suspect they are not classed as SELV, hence the lower requirements on the cable.

    Nick
     
    NickD, Dec 14, 2009
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  12. DDirk

    ashleigh Moderator

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    Whether its a board, a sub-board, a distribution board, a cubicle. Does not matter.

    If it is sealed for the safety of people, and it has mains in it; then the cbus cable insulation rating must be 3750V. Else not in accordance with wiring rules. Therefore illegal. And unsafe. And if you dont have 3750V it and burn the house down the insurer will come after you.
     
    ashleigh, Dec 14, 2009
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