Home  5  Books  5  Magazines  5  News  5  GreenPro  5  HelpDesk  5  Your Cart  5  Register  5  Green Living Forum
Not signed in (Sign In)

Categories

This month's favourite choices




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
 Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




Housing - New Build: How should wiring be fixed in a service void?

Bottom of Page

1 to 30 of 73

  1. <
  2. 1
  3. 2
  4. 3
  5. >
    • CommentAuthorPingy
    • CommentTimeSep 24th 2012
     
    I'm currently fixing my internal airtight membrane to the underside of my vaulted ceilings. I'm taking great care to ensure it is taped and battened to ensure it will stay airtight. The battens will create a 28mm service void to enable any wiring to be routed before plasterboarding.

    My concern is how do I ensure the electrician doesn't come along and tack the wires to the membrane, thereby puncturing and allowing air leakage? What technique should be used for fixing and protecting the wires? Do I need to leave gaps in the battens to allow the wires to pass through? Are the wires tacked to the battens? Should the wires have metal conduit over them so the plasterboard screws don't damage them?

    Soooo many questions....
    • CommentAuthortony
    • CommentTimeSep 24th 2012
     
    clipped to the sides of the battens?
    • CommentAuthornikhoward
    • CommentTimeSep 25th 2012 edited
     
    nice one tony, as ever the simplest ideas are best

    and yes leave the odd gap in a batton

    and be careful with drywall screws

    and ensure circuits are protected by RCD, sparks job anyway and would have to to comply with 17th edition
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 25th 2012
     
    There are 'Installation Methods' specified in the 17th, its all in there and not hard to work out (though a copy of the 17th isn't cheap).
    There are cheaper 'Onsite' guides that will show what you need.
    http://www.amazon.co.uk/s/?ie=UTF8&keywords=on-site+guide+17th+edition&tag=googhydr-21&index=stripbooks&hvadid=6177373616&hvpos=1t1&hvexid=&hvnetw=g&hvrand=518487877307069774&hvpone=&hvptwo=&hvqmt=b&ref=pd_sl_4hbmp4x5qt_b
    • CommentAuthorCav8andrew
    • CommentTimeSep 25th 2012 edited
     
    Do you know what your cabling runs will be, if not could you pre determine this with your electrician and install conduit runs with draw cables. Guess you could have problems with that proposal if you have to cross the curvature of the vaulting.
  6.  
    Is there a lining board behind the membrane? If so, you could give the electrician a choice:

    1. Clip to side of battens;
    2. Where this isn't possible, clip to lining board over single sided butyl tape fixed to membrane.

    David
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012
     
    Posted By: Cav8andrewDo you know what your cabling runs will be, if not could you pre determine this with your electrician and install conduit runs with draw cables. Guess you could have problems with that proposal if you have to cross the curvature of the vaulting.


    This the method that is used in Switzerland and as long as it is planned well it does not create any problems.

    Jonti
  8.  
    Likewise here in Sweden all electrical cabling is run in flexible plastic conduit.
    •  
      CommentAuthorjoe90
    • CommentTimeSep 25th 2012
     
    problem with wire covers or plastic conduit, drywall screws will still go through it!!!!, whenever I fix plasterboard over pipes or cabling I spray paint lines on the plasterboard to show where services are behind the board.
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012
     
    Posted By: joe90problem with wire covers or plastic conduit, drywall screws will still go through it!!!!, whenever I fix plasterboard over pipes or cabling I spray paint lines on the plasterboard to show where services are behind the board.


    Spray paint is great until you decorate. I would suggest using a wire detector before drilling would work and also won't the metal sheath in electrical plastic conduit stop drywall screws?

    Jonti
    •  
      CommentAuthorjoe90
    • CommentTimeSep 25th 2012
     
    jonti, I find the plaster blocks the paint colour from coming through, plus I use a light colour paint. I have not come across a plastic conduit with metal sheath in it, the flexible stuff mentioned above certainly does not have any metal in it. With the hundreds of drywall screws needed for a ceiling I would not want to use a metal detector for every one.

    My mantra "work smarter not harder"
  12.  
    Here the wires have to be 40mm away from the face of the plasterboard - if they're not, they have to be protected in some way. Drywall is typically 12.5mm thick and the screws used are 30mm. In our recent renovation, in a few places where I had wires closer to the surface than this, I protected them with steel strips.

    Paul in Montreal.
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 25th 2012
     
    Posted By: Paul in MontrealHere the wires have to be 40mm

    Pretty sure we have similar rules about the depth a cable is, would have to get my book out to check.
    You might find something here:
    http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=34892
    • CommentAuthorjamesingram
    • CommentTimeSep 25th 2012 edited
     
    as tony said, clip up battons
    regs. state cable must be protected against damage during construction, (so depend on whether your electrician feels they're likely to get damage by PB tacker or not.)
    ,but by running in safe zones , horizantal or vertical of outlet they don't require additonal protection as long as you follow 17th ( ie. protect by addtional RCD). Outside these safe zones they require mechanicial protection <50mm deep
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012 edited
     
    Posted By: joe90jonti, I find the plaster blocks the paint colour from coming through, plus I use a light colour paint.


    SO how do you find cables once the place is decorated?



    Posted By: joe90 I have not come across a plastic conduit with metal sheath in it, the flexible stuff mentioned above certainly does not have any metal in it.


    I suspect you have seen the ribbed flexi but in Switzerland electrics are run through a pipe similar to plastic water pipe and has a metal sheath incoperated into the wall.



    Posted By: joe90 With the hundreds of drywall screws needed for a ceiling I would not want to use a metal detector for every one.


    But in this case you would be drilling into the beaming with the screws where there should be no wiring going below so you need to know where the beams are and any cabling should be out of the way. If I was working attaching say a sign to the ceiling I would still check for cables with a detector wouldn't you?.

    Jonti
    •  
      CommentAuthorjoe90
    • CommentTimeSep 25th 2012
     
    1/ method above only intended for avoiding cables etc during construction

    2/ only ever been a tourist in Switzerland but I dont doubt their methods/regs are good

    3/ only works if you adopt the method described by PIM. Definitely, always check with metal/voltage detector.
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012
     
    Posted By: joe901/
    3/ only works if you adopt the method described by PIM. Definitely, always check with metal/voltage detector.


    What I said in the first place:wink:

    Jonti
    • CommentAuthorCav8andrew
    • CommentTimeSep 25th 2012
     
    Jonti, is the Swiss conduits metal element for tracing, earthing, electrical shielding and/or is it robust enough to resist piercing. Is it flexible enough to remove the need of elbows in most situations. Really like the idea of this never really understood why all cabling is not carried in conduit rather than clipped or left draped.
    joe90 I think many of the companies who manufacture flexible plastic conduit also produce a metal version or a braided, plastic covered version. In fact I'm not sure why I wrote 'could be a problem on the curve of the vaulting' as I investigated the range of products available a couple of months ago and came up with several options of flexi. Adaptaflex, I think, who are one of the big manufacturers of flexible conduit also manufacture a range of metal conduits.
  19.  
    Posted By: Cav8andrewReally like the idea of this never really understood why all cabling is not carried in conduit rather than clipped or left draped.


    Cost and time.

    Paul in Montreal.
    • CommentAuthorCav8andrew
    • CommentTimeSep 25th 2012
     
    Cost and time
    The enemies of a decent build and one that in the long term works against the occupant. Maybe it's also more 'that's not the way we do it' syndrome.
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012
     
    Cav8andrew,

    I presume it is a safety feature. That and the fact that so many builds in Switzerland is done in poured concrete with the conduits in the concrete. I would agree with Paul that it is probably to do with cost here as clips are much cheaper. I suspect it is also that clipping cable is what 'we have always done that way' too.

    It is fairly flexible and if warmed will bend like copper pipe.

    Jonti
    • CommentAuthorjamesingram
    • CommentTimeSep 25th 2012 edited
     
    cost and time ... and why do something that's unnecessary, it's wasteful.
  23.  
    Posted By: jamesingramcost and time ... and why do something that's unnecessary, it's wasteful.


    That was the point I was trying to make! It's a waste of money to put in conduit where it's not needed (the 40mm rule obviates it) plus pulling cable through conduit takes time (which equals more cost), compared to stapling or whatever other cable attachment method is used.

    Over here, I don't think you're allowed to bury cables in plaster/cement/concrete unless they're in conduit, though. I still remember drilling into a buried 240V cable in the wall in my house in the UK in an unexpected location - the sparks that shot out did locate it then, though!

    Paul in Montreal.
    • CommentAuthorjamesingram
    • CommentTimeSep 25th 2012 edited
     
    Yes, i agree Paul , posted this earlier re safe zones and regs. etc.
    Posted By: jamesingramas tony said, clip up battons
    regs. state cable must be protected against damage during construction, (so depend on whether your electrician feels they're likely to get damage by PB tacker or not.)
    ,but by running in safe zones , horizantal or vertical of outlet they don't require additonal protection as long as you follow 17th ( ie. protect by addtional RCD). Outside these safe zones they require mechanicial protection <50mm deep
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012
     
    James & Paul,

    it is always so nice to see a love in.

    Posted By: Paul in Montreal
    I still remember drilling into a buried 240V cable in the wall in my house in the UK in an unexpected location - the sparks that shot out did locate it then, though!

    Paul in Montreal.


    Maybe this would be a reason for better protection:bigsmile:

    I found it a big help in pulling through a telephone extention instead of having to have the cable snaking through the flat in plain view and it also has the advantage that if you want to upgrade or rewire it is really easy to.



    Posted By: jamesingramcost and time ... and why do something that's unnecessary, it's wasteful.


    James, Sounds abit like 'cos we've always done it this way' :wink: though I am sure it is not.
    • CommentAuthorCav8andrew
    • CommentTimeSep 25th 2012
     
    Jonti, would second all you say but then it might seem perilously like a rival love in ! Luckily its my time and money to waste as I please and I'm sure it wont, in reality, be too much of either. Plus adding a bit of end user convenience for later additions cant be bad.
    • CommentAuthorjamesingram
    • CommentTimeSep 25th 2012 edited
     
    Hay chaps , part of an energy efficient 'green' build is not doing the unnecessary and pointless :bigsmile:
    it all depends in your confidence in the accuracy of howevers tacking up the plasterboard.
    Unbelievable as it may sound I've not yet had a cable damaged in 20 years by PB fitting , though it can and does happen.
    If you do choose to use metal conduit of some kind, remember it need to be earthed,as I believe its consider a part of the electric system and may become live under fault conditions ( the deminishing returns of complexity strike again )
    •  
      CommentAuthorSteamyTea
    • CommentTimeSep 25th 2012
     
    There are very strict rules about where a cable can be run and how far it can deviate from the vertical when dropping down to a socket/switch. Horizontal runs are usually done under floors and over ceilings.
    Then there are the permitted zones, and the forbidden zones and then after it is all in there has to be a diagram of what is where (though I know these are rare and generic) Circuits should be clearly labelled as well.
    Being a 'sparky' is quite paper based these days.
    • CommentAuthorJonti
    • CommentTimeSep 25th 2012
     
    SteamyTea,

    all very true and good but its like most government regulation only theoretically followed because it says so on the paper. Forgive my pessimism but, having witnessed three separate self certified electrical installations by accredited companies none of them were close to being within the regs. Because of this and because I live and work in the real world its better safe than sorry and use the detector:bigsmile:

    Jonti
    • CommentAuthornikhoward
    • CommentTimeSep 26th 2012
     
    Use a detector

    Also if cable is in conduit and/or insulation, etc it may need to be de-rated (eg I have heard of 4mm not 2.5 for sockets circuits in domestic wiring). And to prove that being a spark is a paper based activity see regulation 7 and the reference methods in table 4D2A/4D1A or installation methods table 4A2, etc of the big red (now) green book aka BS 7671 aka 17th edition (first amendment) (£80). Or look at little red (now green) book (£20) or guidance notes 1-8 (more expensive books at £25/each)

1 to 30 of 73

  1. <
  2. 1
  3. 2
  4. 3
  5. >
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press