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Electrical Wiring Qu about conduit-work. (UK)

Discussion in 'Do It Yourself (Not Computer-Related)' started by john1, Feb 18, 2006.

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  1. john1

    john1 Thread Starter

    Joined:
    Nov 25, 2000
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    Hi,

    I'm going to be wiring up a small extension,
    and i want to check on the requirements of the current IEE Regs.
    Regarding the conduit-work for housing the electrical cabling.

    I've downloaded the latest 'P-Electrical-safety' from the Govt page,
    http://www.odpm.gov.uk/index.asp?id=1130906
    i've downloaded all three, only the first one seems applicable,
    and i dont see any references at all to conduit-work.

    The only mention i can find is about concealed cabling which may
    need additional protection such as steel conduit.

    *******************
    I found this, at: 'Update-GN1.pdf'

    Where a cable is concealed in a wall or partition at a depth of less
    than 50 mm from the surface of the wall or partition:

    (i) the concealed cable must incorporate an earthed metallic
    covering which complies with the requirements of Chapter 54
    for protective conductors, or

    (ii) be of insulated concentric construction, or

    (iii) the concealed cable must be enclosed in earthed conduit,
    trunking or ducting which satisfies the requirements of
    Chapter 54 for protective conductors or be mechanically
    protected sufficient to prevent penetration of the cable by
    nails, screws and the like.
    ********************

    Which dictates that where wiring is concealed, adequate conduit
    work must be used.

    But i cant find any reference to the conduit-work for
    ordinary house wiring.

    Anyone with any info on this subject, please reply.
    (these regulations are applicable to the UK)

    Cheers, John :)
     
  2. blues_harp28

    blues_harp28 Trusted Advisor

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    Hi for ordinary house wiring..running additonal sockets and switches..electric cable can be covered by plastic conduit...flat conduit for an area that will be plastered over..tubed if conduit is to be left exposed..
    For Additional protection steel conduit is used when wiring is put against exposed brickwork and then cemented or plastered over or in industrial settings where conduit is left exposed..
    All electricians as you know need to NICEIC approved in the UK..Iam not an electrician..but have worked for over 30 yrs in the building trade..
    But in saying that all regulation change almost yearly,and it's best to check with the NICEIC website for up to date regs..
    http://www.niceic.net
    Are you running all cable to the extension from new or replacing old for new??
     
  3. etaf

    etaf Wayne Moderator

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    didnt the rules change in January 2006 in UK and now you are very limited to very minor electrical work as DIY , otherwise you need to have a certified install by certified people
     
  4. blues_harp28

    blues_harp28 Trusted Advisor

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    Hi Thanks etaf heard that was coming..Jan 06 that soon..
    If you are doing the job yourself..you will need an approved electrician to connect your wiring to the consumer box...and he she can run test on what you have done to check for earth leaks etc..but never that happy to do it..as their name goes on the certificate to say all work is up to current regulations..
    Minor work that may be allowed wouldn't include rewiring an extension..
     
  5. buck52

    buck52 Banned

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    Howdy

    No help for you because I'm on the other side of the pond... but

    The rules changed here as well...I am a licensed "construction supervisor" which allows me to permit and build 1&2 family homes up to 35,000 square feet... as well as a home owner ... I built an addition on my house and had to get a friend to "pull" the permit for the wiring... We as homeowners used to be able to pull the permit and do the work ourselves and just pass the final inspection but not anymore...

    buck
     
  6. etaf

    etaf Wayne Moderator

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    yea - i think they have even changed the colour of cable from white to grey and also red/black to brown/blue - so they can tell if work carried out after jan06
    I think
     
  7. blues_harp28

    blues_harp28 Trusted Advisor

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    Hi regulations needed to be changed over here..too many cowboy builders as they are called here doing work that left many homeowners with unsafe properties..
    Even TV programs Builders from Hell..Rouge Traders etc.showing work done by supposedly trained professionals..
     
  8. john1

    john1 Thread Starter

    Joined:
    Nov 25, 2000
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    Hi,

    Yes, the 'rules' have changed.
    There have been several changes, taking effect at different dates,
    and in different categories.

    Building regulations.
    From the 01-01-05 any home and/or garden electrical work must comply
    with the current building regulations. (England and Wales)

    Whether or not this is actually passed into law i dont know, it
    just seems a bit odd that the first rule is
    that you must comply with the rules.

    Anyway thats neither here nor there. I've been an electrician all my
    working life, except for a while when i was a driver.

    I took and obtained the fifteenth regs certificate some years ago,
    some while later i was made redundant and i haven't had a job since.
    Since then there have been further changes, i think the current regs
    are the '18th Regs' but i am not sure .... could be 19 for all i know.

    The electrical work i intend to do is i think 'notifiable' although
    the construction of a small wooden lean-to is not subject to
    planning permission, but must meet the building regulations anyway.
    I will be taking professional advice on any matters involving the
    local authority. Calling it a small extension was probably an
    exaggeration, it's more of a porch by my front door.

    ************************
    Taken from:
    BuildingRegulationsExplanatoryBookletPDF1191Kb_id1131117.pdf
    Which can be downloaded from:
    www.odpm.gov.uk/pub/117/BuildingRegulationsExplanatoryBookletPDF1191Kb_id1131117.pdf

    Extensions to buildings at ground level comprising:

    • a conservatory, porch, covered yard or covered way; or
    • a carport open on at least two sides.

    The extensions must be at ground level only and no larger than 30m sq
    in floor area.Any fixed electrical installation must meet the
    requirements of Part P (‘Electrical safety’).
    Conservatories or porches which are wholly or partly glazed must meet
    the requirements of Part N (‘Glazing – safety in relation to impact,
    opening and cleaning’).
    ************************

    About the colours ....

    *************************
    The colours of the live and neutral wires
    in electrical cables are changing from
    red and black to brown and blue. This is
    the same as the wires in flexible leads to
    portable appliances.
    You can continue to use cables in
    the old colours of red and black
    until 31 March 2006. After that,
    all new wiring must be in the
    new colours.

    Taken from:
    NewrulesforelectricalsafetyinthehomePDF244Kb_id1130908.pdf
    *************************

    This latest rule has a bit more to it than is mentioned in the
    passage above, which i found in a different PDF.
    Although the dates for implemenation are the same.
    You get the impression that you can, if you wish, use the old
    colours up to the end of March 2006.
    But this is not quite the case,
    as from March 2004, it was not permissable to use both colour
    schemes within the same premises,
    i have copied a section from the building regs here to illustrate:

    Quote:
    The new (harmonised) colour cables may be
    used on site from 31 March 2004. New
    installations or alterations to existing
    installations may use either new or old colours,
    but not both, from 31 March 2004 until 31
    March 2006. Only the new colours may be used
    after 31 March 2006.

    Taken from:
    The Building Regulations 2000
    ApproveddocumentPElectricalsafetyPDF901Kb_id1130910.pdf

    So up to March 2006 you could use the old colours if you wished,
    providing that the existing wiring used the old colours,
    cos you are not allowed to use both the old and the new.

    After March 2006 you are only allowed to use the new colours.
    (thats next month)
    ***************************

    Etaf,

    Dunno if it was January, but yes, you are only allowed to do quite
    minor electrical work before you need to get it 'certificated'

    Off-hand i dunno what the extent of 'minor' is, probably changing
    light fittings would be ok, fixed household wiring probably would
    require 'certification' and the respective tests to qualify.

    ***************************

    Back to my original query about conduit-work.

    I can't find much about this, other than what i've already quoted,
    which applies where the wiring is concealed.

    However i think i have figured out why there is no mention of conduit
    apart from situations where the wiring is concealed.
    But i would like to hear more from anyone with any comments about
    the conduit work, im fed up reading about the colours.

    Cheers, John :)
     
  9. john1

    john1 Thread Starter

    Joined:
    Nov 25, 2000
    Messages:
    8,974
    Hi,

    I can find no stipulation that conduit must be used on cabling that is
    not concealed.
    There are requirements about the conduit work where the cabling is
    concealed, such that nails and screws would not penetrate easily.
    And i think conduitwork should be used where single wires are used.

    As this wiring will not be concealed within walls or plasterwork,
    I don't see a requirement for conduitwork.

    As i don't have the latest book of the IEE regs, ive been downloading
    stuff about the regs, and there is an almost unlimited amount of it.
    Ive been reading so much of this stuff, most of it is about colours.
    If there is any stipulation that conduit work should be used,
    please point it out.

    John :)
     
  10. blues_harp28

    blues_harp28 Trusted Advisor

    Joined:
    Jan 9, 2005
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    17,083
    Hi john1 where do you intend to run the cable? for a ceiling light? 13amp socket?
    How long will the cable be?
    You say it's more of a lean to than a room..will there be a ceiling to this lean to?
    Conduit should always be used..unless cable is concealed behind a plasterboard ceiling..
    Behind a stud partition wall..behind skirting-boards..under floorboards..
    If any cable is exposed..the judgement is that it could pose a risk to young and old alike..
    For the small cost of conduit..why not just incase the cable in conduit..
     
  11. john1

    john1 Thread Starter

    Joined:
    Nov 25, 2000
    Messages:
    8,974
    Hi blues_harp28,

    There will be several cable runs, after the end of next month they
    will have to be run in the new colours. I will probably do them all
    in the new colours. There will be a porch light, and a ceiling light
    and their associated switches. There will probably be a socket or
    two also.
    How long will the cable be?
    In all maybe half a roll of lighting,
    maybe half a roll of ring main cable.
    And possibly a length of heavy supply if i feel like it.

    You say it's more of a lean to than a room..will there be a ceiling to this lean to?
    Well what i have in mind is more of an enclosed porch, i will be treating it like a
    small additional room, but it will have to be of a mostly wooden construction to
    qualify as a non-permanent structure. Yes, i intend it to have a ceiling, and to
    look and seem as similar to the other rooms as i can arrange.

    Conduit should always be used..
    you did not mention where you found this,
    this is just the sort of clear and unambiguous instruction that i have been seeking.
    Maybe google could pick it up, if you are quoting the regs ....
    I will give that a try, or maybe you could point me to it.

    For the small cost of conduit..why not just incase the cable in conduit..
    I have a feeling that i probably will use that square looking white plastic conduit
    box-like stuff with the clip-on lid/cover for most of it, open surface wiring always
    seems to look a bit untidy to me.

    So far its my opinion that the only requirement is where the cables are concealed
    within walls, and the stipulation is to protect against screws or nails.
    Ive been going through loads of downloaded stuff about the regs for months now,
    on and off, and i can find no stipulation that conduit must be used,
    other than the following ...

    ********************
    from: 'Update-GN1.pdf'

    Where a cable is concealed in a wall or partition at a depth of less
    than 50 mm from the surface of the wall or partition:

    (i) the concealed cable must incorporate an earthed metallic
    covering which complies with the requirements of Chapter 54
    for protective conductors, or

    (ii) be of insulated concentric construction, or

    (iii) the concealed cable must be enclosed in earthed conduit,
    trunking or ducting which satisfies the requirements of
    Chapter 54 for protective conductors or be mechanically
    protected sufficient to prevent penetration of the cable by
    nails, screws and the like.
    ********************

    It is of course quite possible that i have simply not yet found any clear directive
    about it so far. The regs as i'm sure you know can be heavy going.

    Cheers, John :)
     
  12. blues_harp28

    blues_harp28 Trusted Advisor

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    Hi..Cable for the ceiling light can be hidden under the ceiling..
    Are the walls to be covered with plasterboard or left exposed?
    If plasterboard..no conduit needed..hide behind board..
    If leaving wood exposed..cable can be hidden behind..wood strips..angle beads ect..as long as they are permanent installed..
    The Council and NICEIC main concern will be..is the cable running from the consumer unit correctly installed...correct cable for the ring main..lighting cable..earth bonded..etc..and carrying an up to date NICEIC certificate..
    Not what conduit is being used..
     
  13. john1

    john1 Thread Starter

    Joined:
    Nov 25, 2000
    Messages:
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    Hi,

    I have remembered the name of that square looking white plastic
    conduit, which i mentioned i will probably be using.
    Its called Mini-trunking i think.

    In the absence of any clear pointer to any regulation dictating that
    conduit must always be used,
    and that i have been unable to find any instruction in the regulations
    which insist that conduit must always be used,
    it is my opinion that the use of conduit is not mandatory,
    except for those cases mentioned earlier.

    If anyone thinks otherwise, please refer to the relevant regulation
    because it is extremely difficult to locate references without some
    where to start.

    I am now trying to find out if that thin metal covering for cabling
    which is often used for plastering over is still acceptable.
    I realise that it would not provide much mechanical protection against
    a nail or a screw which might penetrate through to the conductors,
    but it should operate the current trip sensor, if such happened.

    Would that be acceptable?
    On the face of it, no it wouldn't, the regulation clearly states:
    Quote:
    the requirements of
    Chapter 54 for protective conductors or be mechanically
    protected sufficient to prevent penetration of the cable by
    nails, screws and the like.

    Again, its difficult to be sure, it may be acceptable for lighting
    if an RCD device is also used, but unacceptable for power points.
    Sometimes there are 'qualifying' paragraphs that seem to have been
    added later.

    John :)
     
  14. blues_harp28

    blues_harp28 Trusted Advisor

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    Hi john1..you say using conduit will look messy..
    Imagine seeing the cable running everwhere held by just cable clips?
    I was on a job on monday..on the roof laying some lead gutters went down for a cup of tea as you do and the electrician NICEIC approved was running 30amp cable from the consumer box to the kitchen for the cooker..
    Couldn't run it under the floorboards..old church flooring was unmoveable..so it had to be run in plastic trunking [ordinary conduit from Wickes] along the skirting..
    30 amp cable running in plastic conduit..
    For what you are about to do..ring main..lighting cable..ordinary conduit will do the trick..
    Why you can't find any building regs for condiut I have no idea..
    As you know the reason for conduit is to protect the cable and to make it visible that electric cable is present..
    The thin metal covering you mention is made of steel..and even a drill bit would have a tough job penetrating it.
     
  15. john1

    john1 Thread Starter

    Joined:
    Nov 25, 2000
    Messages:
    8,974
    Hi blues_harp28,

    I do appreciate your advice and comments, but i didn't say that using conduit
    would look messy.
    Pretty much the reverse actually, that open surface wiring often looks rather
    untidy to me.
    Not that i can find any regulations against open surface wiring, in fact one
    of the persons i asked pointed out that the manufacturers ratings for cables
    is normally for free open air on one side. Typically fastened with cable
    clips. I have not checked that, but he seemed like he knew his stuff.
    When i am asked to do open surface wiring i take a lot of trouble over placing
    the clips and in making the cable run as neat and straight as i can.
    Probably because it annoys me when open surface wiring is run untidily.
    Using trunking or similar conduit work would obviously be much neater and
    tidier than just cable clips.

    As to the electrician that you saw running the cooker feed from the fusebox
    to the cooker point, it is difficult to comment. Presumably the electrician
    had looked at what options were available and had chosen his route carefully.

    Personally i would avoid using the skirting board for cable runs, as i have
    seen someone pick up a chair, walk over to where he wanted to sit with the
    chair, and place the chair sideways against the wall, and sit on the chair
    as it neared the floor.
    The legs of the chair actually rubbed against the wiring along the skirting
    which was only telephone wiring, whether it made any difference to the phone
    i don't know, but it stuck in my mind that some people simply have no care
    or appreciation of their actions.

    Skirting boards could be easily damaged by metal table legs, or chair legs,
    or even peoples chunky shoes, but maybe this situation is never likely to
    meet any such conditions.
    A church ... ive never done any wiring in a church.

    Quote:
    Why you can't find any building regs for condiut I have no idea..


    Actually i have found a few regs about conduit,
    but i am trying to find out if conduit 'must' always be used,
    and as far as i can tell the regs do not forbid open surface wiring,
    nor can i find any regulation that says conduit 'must' always be used.
    (apart from the particular situations mentioned earlier)
    For which i have quoted the sources.

    The metal covering i mentioned is for putting over a cable which is placed
    in position usually on a wall to be plastered, and from what i recall the
    metal covering would be nailed into place with short galvanised nails on
    the sides of the metal covering.
    From what i recall no great problem was found when banging in the fixing
    nails for the metal covering, they seemed to go through it and into the wall
    without any trouble.

    This is what made me wonder about the stipulation for mechanical protection
    as described in chapter 54 of the latest regulations.
    Such metalwork would clearly not provide adequate mechanical protection, but
    i would guess that the protection from the 'trip' would operate if a nail
    were to penetrate into the electrical conductors, providing of course that
    the metalwork was adequately earthed.
    Where metalwork below a given size is within the structure of the masonry
    such as 'wall-ties', or those bits of metal cornering for plasterwork, it
    could be that earthing is not obligatory if such metalwork is not actually
    exposed at any point. This i don't know, but it is possible.

    It could be that any metal covering for cabling now has to be earthed/bonded
    which i don't think has always been the case.
    Even so, would the bonding consitute compliance to chapter 54 ... ?

    I think that it would not, as it calls adequate for mechanical protection,
    and i quote:
    mechanically protected sufficient to prevent penetration of the cable by
    nails, screws and the like.


    It would be almost impossible to protect against a nail from one of those
    hand held nail guns which are now in regular use, some bigger than others.
    Some of them are capable of actually nailing things directly on to heavy
    girder-work.

    So maybe the electrical 'trip' would be acceptable as protection ... ?

    In the absence of any clear directive i don't think i will be concealing
    any cabling within the walls. I will probably have it in trunking where it
    comes down vertically to the points and switches.

    Cheers, John :)
     
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