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Thread: Ducting in a roof

  1. #1
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    Ducting in a roof

    New question. Residential house has a ducting running from the one end to the other end (wireway/trunking..whatever you want to call it). All the cables are fed from this ducting via surfix, twin & earth, steel piping and pvc. The come out at 90degree angles to their relative load points.

    Hear my thoughts.....inside the ducting is armored, twin & earth, surfix and GP wire. The ducting is not closed. Taking the law in perspective, not what is best practice, is it legal to run the GP wire in the ducting while the entire wireway's cover is no longer available. Before you answer, consider this...open wiring is still legal, not preferable, but legal. Open wiring is classified as two conductors running side by side on porcelain blocks X cm apart and supported at Y cm. The wire in the ducting although not fit on porcelain blocks, is fully supported and protected from mechanical strain and damage??

    The question; is the ducting legal with no cover (keep in mind that the house was built 20 years ago, and replacing all the wires would be expensive)?
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    Email problem 123's Avatar
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    The existing installation would be assessed under Clause 5 of sans10142, General Safety principles. One reference I found was 5.2.8 (d) and (e):

    Electrical equipment shall be so positioned that:

    d) it is not likely to be physically damaged, Amdt 3
    e) dust or moisture is not likely to accumulate on live or other parts and cause flashover. Amdt 3.

    I guess if you leave the ducting open, and let's say they replace tiles or do any other work in the roof, there is a good chance that the GP wiring might be damaged. Again this is only true for the existing part of the installation. The effected alterations, extensions or additions still has to be fully compliant. The act clearly states effected. If you did not effect the alterations or additions, then it defaults back under existing installation and has to comply with clause 5 only of sans 10142.

    Another Reg that is applicable, is 3.84.2, and it defines ducting:

    3.84.2
    ducting
    closed enclosure that allows insulated conductors and cables in electrical installations to be drawn in and to be replaced. Amdt 1
    If it is not broken, fix/test it until it is.
    This is my opinion and I stick to it.

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    Site Caretaker Dave A's Avatar
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    My question is why the heck someone didn't put the cover on the trunking/ducting in the first place?
    The trouble with opportunity is it normally comes dressed up as work.

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    Quote Originally Posted by 123 View Post
    The existing installation would be assessed under Clause 5 of sans10142, General Safety principles. One reference I found was 5.2.8 (d) and (e):

    Electrical equipment shall be so positioned that:

    d) it is not likely to be physically damaged, Amdt 3
    e) dust or moisture is not likely to accumulate on live or other parts and cause flashover. Amdt 3.

    I guess if you leave the ducting open, and let's say they replace tiles or do any other work in the roof, there is a good chance that the GP wiring might be damaged. Again this is only true for the existing part of the installation. The effected alterations, extensions or additions still has to be fully compliant. The act clearly states effected. If you did not effect the alterations or additions, then it defaults back under existing installation and has to comply with clause 5 only of sans 10142.

    Another Reg that is applicable, is 3.84.2, and it defines ducting:

    3.84.2
    ducting
    closed enclosure that allows insulated conductors and cables in electrical installations to be drawn in and to be replaced. Amdt 1
    I agree, but still, open wiring is legal. In theory, if you wanted to wire a house on that method you cannot be faulted. And open wiring is gp wire running on porcelain holders, so, isn't open wiring rinning in a ducting at least a bit safer then?

    I'll tell why the question, SANS says: If any part of the installation is altered/renewed/modified....then the entire installation must comply to SANS 10142, regardless of its year of origin. I have a pensioner whom has this ducting in his roof. Soon he will need to get a COC. I refuse to rip people off, regardless of who they are. I will have to already change plenty of things on his house without even looking at the ducting or the cables inside. How I see it, the sides of the ducting is at least 10cm high, and the cables only fill up 3cm. So anything or any body has to go into the ducting at around 7-8cm to even touch the wires. If it was open wiring (legal), you could step on it with ease, extremely crappy way of wiring (my pers. opin.).....so in theory, this ducting is safer?
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  7. #5
    Email problem 123's Avatar
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    Quote Originally Posted by Jacques#1 View Post
    I'll tell why the question, SANS says: If any part of the installation is altered/renewed/modified....then the entire installation must comply to SANS 10142, regardless of its year of origin.
    Now you have me worried. Can you please point me to the Sans reg. or OHS act which state the above? I was under the impression that the act makes provision explicitly for a) New installations , b) existing installations and c) Existing installations (to comply with clause 5 of sans) and the effected alterations/extensions to comply with complete sans 10142.

    To try and answer the question, my opinion would be to just close the ducting, get someone with the equipment (bender/cutters) to manufacture the cover, screw it on the ducting. Make sure all exit and entry conductors/cables is mechanically protected at entry/exit points at the ducting. (ps it is ducting? not a cable rack?) and yes you are correct, it seems open wiring type is compliant, as long as it complies with sans 6.4.5 and 6.4.6, and if Wireways is used the 6.5 as well. But if the installation is an old installation (20 years+? you said?) then it is excluded from a type (b) or (c) (OHS Act) certification. (??)

    I am always confused, it just varies on quality.... :-)
    Last edited by 123; 22-Apr-10 at 09:02 AM.
    If it is not broken, fix/test it until it is.
    This is my opinion and I stick to it.

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    When I did my Installation courses etc. I was taught that you do get new/existing installations. This is specific to testing for a whole site like a guy wanting to sell.

    When doing an existing installation: If there has been no changes to the ENTIRE system, then you can work off the pre/post 1992 law. Keep in mind that replacing an item e.g. a light or a breaker is not changing/altering the system (as I see it).

    Obviously, if you test and the system was post 1992, the it must comply to SANS 10142. If you test a prior to 1992, then you can work off "reasonably" safe. If there was a change made, eg. a new light cable was chased into the wall, an additional switch added and the system is prior 1992, then it must be updated to post 1992 i.e. SANS10142. Usually there is nothing wrong with the wiring, as steel piping, open wiring etc. is still legal. But, the DB needs some TLC, the Geyser needs an isolator as well as the gate motor and other fixed appliances. When doing this you test the whole system, because you did not install the stuff, you got there after the fact, the owner wants a COC for the entire installation.

    When doing an altered installation: The altered installation will feed off a breaker in the Main DB board or something similar. The work that you have personally done, you can issue a COC for, it will be post 1992. You will not issue a COC for the entire installation. This changes when another guy gets there and has to issue a COC for the entire system. He will then test your work as well as the existing installation, which would mean it will be post 1992. You cannot issue 2 COCs for a house, one for altered work and one for existing work. This would in a legal sense mean that you can for every new SO or whatever do a COC, and not have to install an earth leakage and isolators because of the age of the installation....to me it doesn't make sense.

    This is what I was taught, my views/comments on it anyway.
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  9. #7
    Email problem 123's Avatar
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    Just a few points to consider: The term "before 1992" is not part of the new legislation. It has been changed to "the publication of the last amendment of SANS 10142-1", and I believe the new SANS was published last year with new amendments.

    So, an existing installation, according to the briefing I went to, and according to the new act, is any installation that existed before the date of the last publication of SANS 10142-1. Now this was approved in November 2009 and is also the date valid for publication (Page 3(b)) in SANS 10142-1: 2009.

    The act also clearly states that an existing installation (part 9. (b) of the act) should only comply with Clause 5 of sans 10142-1:2009, which is the "general safety principles".

    It goes further to say that "EFFECTED" alterations or extensions, and please note, it does not say "AFFECTED", it says effected (something that was done), should comply with the complete rules and regs of sans 10142-1: 2009.

    For some reasons, at the presentations I went to, the word "affected" was used, instead of "effected", which can create major misconceptions in our trade, which in turn leads to a total rip-off towards the public.

    If your alterations or extensions which you have done (effected), should cause any part of the existing installation to be non-compliant with the general safety principles (again, only clause 5 of sans10142), you should rectify that situation so that it does comply with clause 5.

    Such alterations or extensions that you have effected however, must be fully compliant.

    Clause 7. (3) of the act also states:

    (3) Subregulation (1) shall not apply to an electrical installation that existed prior to 23 October 1992, and where there was no change of ownership after 1 March 1994: Provided that, if any addition or alteration is effected to such an electrical installation, the user or lessor of the electrical installation, as the case may be, shall obtain a certificate of compliance for the whole electrical installation, whereafter the provisions of subregulation (1) shall be applicable to such electrical installation.

    7. (1) Subject to the provisions of subregulation (3), every user or lessor of an electrical installation, as the case may be, shall have a valid certificate of compliance for that installation in the form of Annexure 1, which shall be accompanied by a test report in the format approved by the chief inspector, in respect of every such electrical installation.


    Which i understand as: You do not need a COC if the installation existed before 23 October 1992 AND there was no change of ownership, otherwise you "shall" obtain a valid CoC.

    Which bring us right back to the three types of CoC's classified as valid by the act: a) New,- Complete SANS, b) Existing,-Clause 5 only of SANS and c) Existing with extensions/alteration under your general control.-Clause 5 for the old part and complete sans for the new parts which you have done under your general control.

    A new installation is one build from the ground up, now. When you are done, the installation should be assessed as new.
    Last edited by 123; 22-Apr-10 at 06:20 PM.
    If it is not broken, fix/test it until it is.
    This is my opinion and I stick to it.

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    I do believe that we are saying the same thing. Section 5.1, 5.2, and 5.3 for a new installation, 5.4 both blocks for an older one before October 1992.

    I have ammendment 6 (last year), I know there is a later version which came out this year, but it only includes the addition of the DOL letter on the COC as far as I know.

    At the part of the book in the annexures at testing and inspection, it still refers to pre and post 1992 October, where SANS 10142 is/is not applicable.

    You have me worried now, because the book is not clear at another point, and I am confused. Very plainly put: If I get to a house, built in 1957, there is no earth leakage, and no main switch, but they installed 10 new socket outlets and 10 new lights, this is ok because the house is prior to 1992, but the alteration does not affect the old installation? Or, the geyser cables melted, and they replaced the CB, cables and element, but the geyser and house is pre 1992 so no isolator is needed?

    So what do you do, do you fill in the house and all the CB's on the existing bit, and the new CB's and SO on the altered bit? I am seee rrrrr iiii ooooo ssss lllll yyyyy confused, this doesn't make sense at all? I thought the drive in the electrical legislation was to eventually get the old wiring methods out, this being done by demanding COC's and updates to the new laws is alterations was made?
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    Maybe to avoid confusing myself more I must ask this differently....A guy plans on moving and asks you for a COC. the house was built in 1980, but he has installed a lot of stuff a week ago (himself). There is no Earth leakage. Do you give him a COC, or do you say sorry sir, but I need to add an Earth Leakage because thats the law and you have altered your installation making it post October 1992.
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  12. #10
    Gold Member garthu's Avatar
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    My understanding, if the work was 1980 and no earth leakage, no problem (really stand to be corrected) BUT what i am 99.9% sure on if yoy changed anything a week ago, must be fully compliant.
    Garth

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