Plastic capping......whats it purpose?

Discussion in 'Electricians' Talk' started by sparky Si-Fi, Apr 28, 2004.

  1. The Trician

    The Trician New Member

    Cheers Tel,

    My point exactly.

    TT
     
  2. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    Well this certainly has produced some feedback,

    The reason behind the query is that I am in the middle of first fixing some addiions/alterations on a 'turn of the century' house.

    The SDS didnt like chasing out the cotswold stone and trying to get Galvanized to stay put on the 'bumpy' wall,well give up on that,so used PVC,done the trick though nicely.

    Also,anyone got any probs about wrapping a bit of tape every foot or so to keep the cables together so to aid the positioning?

    SF
     
  3. Lectrician

    Lectrician Screwfix Select

    exactly what the other posts above have said..who sad oval or capping did give penetration protection.....the pixies in ya head?
     
  4. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    what you mean m8?
     
  5. The Trician

    The Trician New Member

    S/F - I don't like bunching cables together with tape - it makes it a real pain of a job if you need to follow a cable, or need to remove a single for any reason but that's my opinion mate. If it helps hold the things in place, then tape away my friend! Tape away!

    TT
     
  6. Rabbit Rabbit

    Rabbit Rabbit New Member

    The ONLY time I use tape (and by that I mean insulating tape) is when I am about to chisel someones wall - I use the tape to hold poly sheet to the wall to stop dust getting down to the carpet, then I dump it!

    As for capping I think we are all agreed - it provide NO protection at all - be it plastic, metal, titanuim or whatever as TT rightly says an SDS+ will make mincemeat of them all.

    Looks nice though lol
     
  7. The Trician

    The Trician New Member

    exactly what the other posts above have said..who sad
    oval or capping did give penetration
    protection.....the pixies in ya head?

    If you took the time to read the first post from the original poster you'd have heeded the question he was asking about regulations concerning the use of capping to provide mechanical protection mate.

    Nuff said.

    TT
     
  8. ban-all-sheds

    ban-all-sheds New Member

    TT - your excuse for saying what you did doesn't wash. Here's the precis of the thread, with nothing germane omitted:

    <u>sparky sifi</u>: why is plastic cable capping readily available, as it does not prevent the penetration of nails,screws and the like

    <u>scotspark</u>: metal capping dont offer any protection either. i mean you put it up with clip nails so if you drill or nail into the wall the only chance youve got is if you hear it

    <u>Damocles</u>: Thought the idea was to create a tunnel so you can pull another wire through in the future if you have to, without smashing the wall to pieces

    <u>rabbit rabbit</u>: I think Damocles has it in one and it ssort of protects the cables within against plaster. It offers no protection, just like metal capping

    <u>SWA</u>: I always thought plastic and metal capping was just for mechanical protection during the building process, ie plasters trowels etc, ...as mentioned, neither plastic or steel capping satifies the requirement to prevent nail penetration

    <u>Lectrician</u>: plastic, galvanised metal, its upto you, its to protect the cables whilst the plasters plaster the wall, it isnt to protect against penetration ATALL. Best to use oval tube, you can remove and reinstall cables easily with this

    <u>rabbit rabbit</u>: I used to use oval all the time, it's MUCH better than plastic or metal capping. As you quite rightly say some sparky in the future will thank you for using oval when he has to draw throgh another or replace the cable

    <u>Lectrician</u>: have you seen the damage a plasterers trowl can do a pvc cable clipped to the wall? The oval tube (or capping if you really are trying to save money) is there truly only to protect the cable,

    <u>sparks</u>: oval tube is a far better job than capping and with 20mm oval you can get it right inside the assessory box, I've always understool that the capping is there just to protect the cable during construction as we all know it provides no protection against drills, nails or screws etc.

    And then you come along and say "But - can anyone explain to me why they believe that oval plastic conduit provides more protection against nails/screws/masonary drills?"

    Then a whole bunch of people reiterated that they had never said it did that, and asked what you were on about, and you tried to justify what you'd written by saying "If you took the time to read the first post from the original poster you'd have heeded the question he was asking about regulations concerning the use of capping to provide mechanical protection"

    It doesn't work TT, you really didn't pay attention - the original poster asked why there was capping etc as it didn't provide mechanical protection, everybody agreed and said what capping was for, and how oval tube was also available, and was better at those things than capping. Not once was it claimed that it provided protection against nails etc, and you can't possibly say that you asked why people said it did when they didn't because the original poster asked why there was capping. You asked why people said it did when they didn't because you didn't read it properly.

    It's ironic too that when the only method that has a hope of working, i.e. steel conduit, was suggested, you dismissed it as a joke.

    So tell us - whether you think the regs make any sense or not, what do you use when mechanical protection is required?

    You have to sign a document where you state
    So what do you do, TT? If you know that the regs require mechanical protection, and you know that plastic doesn't do it, and you don't use steel conduit as you think that's a joke in domestic situations, how do you make that declaration? Do you state in the list of departures "no mechanical protection provided to cables"?
     
  9. Damocles

    Damocles New Member

    Blimey BAS, better run out and buy a few carriage retun nails to hold those lines down a bit
     
  10. ban-all-sheds

    ban-all-sheds New Member

    Yo - sorry 'bout that.

    I wanted a font which was slightly different for the quote from the certificate, so I used [ pre ][ /pre ], and that puts it in exactly as typed, no wrapping.

    C&N bulletin board s/w, IMHO.
     
  11. ban-all-sheds

    ban-all-sheds New Member

    C&N bulletin board s/w, IMHO.

    Plus a nut loose on the keyboard ;)
     
  12. Ex- Leccy

    Ex- Leccy New Member

    I was told many years ago that capping metal or pvc,was not for protection but to allow an air gap around the cables to help prevent them from overheating/sweating.
     
  13. Lectrician

    Lectrician Screwfix Select

    air gap? my ar se
     
  14. gerrin2owd

    gerrin2owd New Member

    I have a different theory that was told to me by an electrician many years ago regarding metal capping (plastic capping wern't around then), that the capping was installed over rubber cables to prevent lime, used in plaster at that time, from attacking the cables (chemical reaction).

    I do not know if this is true but I believed it!

    I think Sparki sifi is correct in saying:-
    so what we are saying that using the pvc capping we are more than satisfying Regulation 522-06-06.
    and in defence of TT regarding conduit, I assume he means that the domestic spark wouln't have conduit and bender etc in the van so he doesn't run cables diagonally. :)
     
  15. Lectrician

    Lectrician Screwfix Select

    agree gerr....d

    back in the old rubber and lime days, but today, its a different story.

    Enough of this topic, we know what answers are right and which ones are daft :)
     
  16. The Trician

    The Trician New Member

    TT - your excuse for saying what you did doesn't
    wash. Here's the precis of the thread, with nothing
    germane omitted:

    <u>sparky sifi</u>: why is plastic cable capping
    readily available, as it does not prevent the
    penetration of nails,screws and the like


    <u>scotspark</u>: metal capping dont offer any
    protection either. i mean you put it up with clip
    nails so if you drill or nail into the wall the only
    chance youve got is if you hear it


    <u>Damocles</u>: Thought the idea was to create a
    tunnel so you can pull another wire through in the
    future if you have to, without smashing the wall to
    pieces


    <u>rabbit rabbit</u>: I think Damocles has it in
    one and it ssort of protects the cables within
    against plaster. It offers no protection, just like
    metal capping


    <u>SWA</u>: I always thought plastic and metal
    capping was just for mechanical protection during the
    building process, ie plasters trowels etc, ...as
    mentioned, neither plastic or steel capping satifies
    the requirement to prevent nail penetration


    <u>Lectrician</u>: plastic, galvanised metal, its
    upto you, its to protect the cables whilst the
    plasters plaster the wall, it isnt to protect against
    penetration ATALL.
    Best to use oval tube,
    you can remove and reinstall cables easily with
    this


    <u>rabbit rabbit</u>: I used to use oval all the
    time, it's MUCH better than plastic or metal capping.
    As you quite rightly say some sparky in the future
    will thank you for using oval when he has to draw
    throgh another or replace the cable


    <u>Lectrician</u>: have you seen the damage a
    plasterers trowl can do a pvc cable clipped to the
    wall? The oval tube (or capping if you really are
    trying to save money) is there truly only to protect
    the cable,


    <u>sparks</u>: oval tube is a far better job than
    capping and with 20mm oval you can get it right
    inside the assessory box, I've always understool that
    the capping is there just to protect the cable during
    construction as we all know it provides no protection
    against drills, nails or screws etc.


    And then you come along and say "But - can anyone
    explain to me why they believe that oval plastic
    conduit provides more protection against
    nails/screws/masonary drills?
    "

    Then a whole bunch of people reiterated that they had
    never said it did that, and asked what you were on
    about, and you tried to justify what you'd written by
    saying "If you took the time to read the first
    post from the original poster you'd have heeded the
    question he was asking about regulations concerning
    the use of capping to provide mechanical
    protection
    "

    It doesn't work TT, you really didn't pay attention -
    the original poster asked why there was capping etc
    as it didn't provide mechanical protection, everybody
    agreed and said what capping was for, and how oval
    tube was also available, and was better at those
    things than capping. Not once was it claimed that
    it provided protection against nails etc
    , and you
    can't possibly say that you asked why people said it
    did when they didn't because the original poster
    asked why there was capping. You asked why
    people said it did when they didn't because you
    didn't read it properly
    .

    It's ironic too that when the only method that has a
    hope of working, i.e. steel conduit, was suggested,
    you dismissed it as a joke.

    So tell us - whether you think the regs make any
    sense or not, what do you use when
    mechanical protection is required?

    You have to sign a document where you state
    So what do you do, TT? If you know
    that the regs require mechanical protection, and you
    know that plastic doesn't do it, and
    you don't use steel conduit as you
    think that's a joke in domestic situations, how do
    you make that declaration? Do you state in the list
    of departures "no mechanical protection provided to
    cables"?

    B-A-S

    The inference I gained from reading successive posts both on this thread and on others has been the use of plastic, or metal capping/oval conduit etc etc, hence the title of this thread - "Plastic capping... what is its purpose?"

    Successive responses, which you have quoted at length, mention mechanical protection as being one of the uses.
    The thread then goes on to mention the merits or otherwise of plastic Vs metal capping, and capping Vs oval conduit by the various contributors.

    I merely questioned, and went on to point out that neither methods provide mechanical protection against nails/screws/drills.

    The only time I have EVER seen steel conduit in a domestic environment, is when a property has been converted from its former use as offices, or was a former school for example.

    BS7671 DOES NOT require the use of steel conduit as a prerequisite in domestic properties as far as I know.

    TT
     
  17. The Trician

    The Trician New Member

    Just to expand the point - I take the view that if a circuit has been correctly designed and the Inspection & Test results meet the Regulatory requirements, then the risk posed by an unprotected cable buried in plaster is negligible.

    Upon the occurence of a fault due to mechanical damage, the protective device should disconnect the circuit in the required time.

    TT
     
  18. The Trician

    The Trician New Member

    Re: cables in capping to provide an air gap to prevent overheating - PVC cable is rated up to 70'C.
    Also, the open ends of the capping are usually filled up with plaster by the time the plasterer has finished!

    I use plastic capping simply because its the cheapest, and there's no advantage in increased protection to be gained from the use of steel.

    TT
     
  19. Damocles

    Damocles New Member

    please no one re-post that last long one again with additions!

    I guess that with more RCD about the risk of shock from driving a nail nicely through the live and then grabbing hold of it is less than it used to be. I remember previously someone observed that capping would likely feel strange if you try to drive a nail through it, giving some idea of a problem.

    I dont know about plasterers, are they really that crazy to go chopping at the cables, pvc is quite tough in normal handling.
     
  20. gerrin2owd

    gerrin2owd New Member

    Some plasterers ARE "really that crazy to go chopping at the cables". Leave your cables hanging out the socket boxes on the 1st fix and some ar se ole plasterer cuts the "tails" off leaving them too bl00dy short!
    Thats a real downer :(
     

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