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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthorPetlyn
    • CommentTimeMar 20th 2020
    Looking for some advice - I'm sure someone knows the answer to my query ...

    We have concrete wideslab flooring to both ground and first floors and as a result have installed maxi trunking beneath the first floor to accommodate all electrical wiring (single cables not twin & earth); all cables were placed in conduit, chased into the walls prior to to plastering.

    We have several outlets identified for cat 5 cable - is it possible to place the cat 5 cable in the maxi trunking along with the electrical cables - probably not - if no, would placing the cat 5 cable within another conduit before placing in the trunking be an option? If no again, would placing the cat 5 cable in a conduit and then fixing above the maxi trunking be the solution? This would keep electrical cables and the cat 5 cable about 100mm apart.

    Any recommendations/suggestions would be gratefully received.

    Thanks folks.
    As far as I know cat 5 or 6 cables should not be in the same conduit as (or next to) mains cable. If there is no choice then use a shielded cat 5 cable. If an additional conduit is used then it should be metal and earthed bonded (effectively making a shielded cable). For best a separation of about 20-30cm should be designed in but any separation will help, it depends upon the distance of parallel running as to the amount of interference experienced.
    • CommentAuthorgoodevans
    • CommentTimeMar 21st 2020
    Safety and code/rules aside (I have no experience here) - the number of times I have come across power cables having any affect on data cable is zero.

    My gut says the 50Hz AC power is too low a frequency to have an effect on the data signals. however spikes and other noise in the power cable may have an effect (again I think low risk). If there were a problem I would look at locating noisy frequently switching items such as USB chargers, florescent & led lighting, anything that says 'inverter technology' All these items should smooth the power draw - but under fault conditions MAY cause problems.

    I predict you will have no problems - keep it simple, use regular UTP cabling and all will be well (asaik to get the benefit of shielded cables careful attention needs to be taken to earth the shielding - I think at one end only - but it is complicated I think.
    • CommentAuthorMatBlack
    • CommentTimeMar 21st 2020
    Hard to seperate fully in reality, but do the seperate run. For the relatively little extra, its worth using cat 6 instead for a bit of future proofing. Its a bit less flexible cable though, steady on the bends.
    • CommentTimeMar 21st 2020
    Posted By: MatBlackFor the relatively little extra, its worth using cat 6 instead for a bit of future proofing. Its a bit less flexible cable though, steady on the bends.

    For myself, I took the opposite decision, that the extra complexity of meeting the cat6 bending and connection rules wasn't worth it given my likely usage. I can't see me needing more than a gigabit to any device, and switched fabric means connections don't need to be shared.

    It's perhaps worth pointing out that there are flexible cables, which use stranded wire, and less flexible ones, which use solid core. The solid core is intended for permanent installation and the stranded is for patch cables that undergo repeated flexing.
    • CommentAuthorXT600
    • CommentTimeMar 22nd 2020
    I've always run band 1 ( data cables etc) separately to band 2 (typical domestic voltages) where possible. However, in reality this isn't always possible and as far as regs go then a separate divider inside your trunking would be your best bet. However, because you've used singles rather than twin/earth, it's probably safer to run in a separate conduit if possible. As has already been said, it's doubtful you'll have any interference problems but the issue is more that you need to minimise the possibility of higher voltages being present in the data cables (for which their insulation is not designed) under fault conditions. Should a fault occur causing the mains cable to overheat and melt and contact the data cables then this could be a dangerous situation. Having said that, it's highly unlikely given today's standards of work and equipment used to prevent over-current and earth faults. In your case, if the cables are already in place then there's probably little you can do other than start again. If it were my house, I wouldn't be losing sleep over it :bigsmile:
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