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Discuss Flying leads and the regulations. in the Electrical Wiring, Theories and Regulations area at ElectrciansForums.co.uk.

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  1. steve snakeman
    Online

    steve snakeman Guest

    can anyone tell me where in the 17th edition it tells you in black and white that you do not need a flying lead attatched to metal back boxes from a socket.Also the same for a steel sink in a kitchen.I have been reading it all day and have a sore head.Thanks.
     
  2. telectrix
    Offline

    telectrix Scouser and Proud of It Respected Member

    Location:
    cheshire/staffordshire
    Business Name:
    Telectrix
    more to the point, where does it tell you that you have to bond kitchen sinks? sinks are not exranneous conductive parts unless the waste is metallic, in which case, the waste would need bonding. and it was back in the 16th, around 2003, trhat the need for flying leads was dropped as long as there was 1 fixed lug on the backbox. however, myself and a lot of other sparks prefer to fit a fly lead, if only to ensure that the backbox is earthed if the faceplate screws/pins are removed.
     
    • Like Like x 7
  3. steve snakeman
    Online

    steve snakeman Guest

    Thanks for the reply.I am aware of all of the above and also put in a flying lead however I have been asked to a meeting on Monday where I have to prove my point .Another electrician tested a collegues work where no flying leads were present and listed them as class 1 faults on his condition report.I defended my partners work by explaning this and have been asked to prove it :(
     
  4. tony mc
    Offline

    tony mc Electrician's Arms

    This is on the ESC website.

    I would love to see what other code 1 observations were made if he classes this as Danger present Risk of injury.

    So what did he do to elimanate that risk????????
    [TABLE]
    [TR]
    [TD][TABLE="class: mainblock"]
    [TR]
    [TD="class: sectiontitle"]SOCKET-OUTLET(S)[/TD]
    [TD="class: bigletter, width: 100"]S[/TD]
    [TD="class: sectiontitle2, width: 100, align: center"]S181-5[/TD]
    [/TR]
    [TR]
    [TD="class: topictitle"]Earthing of enclosure (back box)[/TD]
    [/TR]
    [/TABLE]
    Contents
    1. Introduction

    2. Where the cpc is a single-core cable or a core of a cable, connected directly into the earthing terminal of a socket-outlet
    2.1 Metallic box with two fixed (non-adjustable) lugs
    2.2 Metallic box with two adjustable lugs
    2.3 Metallic box with one fixed and one adjustable lug

    3. Where the cpc is formed by metallic conduit, trunking or ducting, or the metal sheath or armour of a cable


    1. Introduction
    Guidance is provided in this topic on whether it is necessary to install a so-called ‘earthing tail’ between a socket-outlet and an associated metallic back box. The guidance applies where protection against electric shock is by automatic disconnection of supply, as it is in the vast majority of cases.
    A metallic back box for a surface-mounted socket-outlet is an exposed-conductive-part, and a metallic back box for a flush-mounted socket-outlet is deemed to be an exposed-conductive-part (even though it may not be able to be touched). Therefore, such back boxes, no less than every other exposed-conductive-part, are required to be earthed in accordance with Regulations 411.4.2 (TN systems) and 411.5.1 (TT systems) of BS 7671.
    However, depending upon certain characteristics of the circuit protective conductor (cpc), the socket-outlet and its box, an ‘earthing tail’ may or may not be required between the socket-outlet and back box.

    2. Where the cpc is a single-core cable or a core of a cable, connected directly into the earthing terminal of a socket-outlet
    An earthing tail may not be required where the cpc associated with the circuit wiring from a distribution board to a socket-outlet takes the form of a single-core cable or a core of a cable, and is connected directly to the earthing terminal of the socket-outlet.
    Whether an earthing tail is required depends upon whether one or both of the lugs on the back box are adjustable (to permit the socket-outlet to be levelled), and upon the earthing strap and eyelet arrangement of the socket-outlet, as detailed in items 2.1, 2.2 and 2.3.


    [/TD]
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    [​IMG][/TD]
    [TD]2.1 Metallic box with two fixed (non-adjustable) lugs
    The provision of an earthing tail is not required between a socket-outlet having an earthing strap and either one or two eyelets, and metallic back box as shown in Fig 1 (although the fitting of an earthing tail is still desirable). The box can be considered adequately earthed through the earthing straps and eyelets of the socket-outlet and the fixing lugs on the box.

    2.2 Metallic box with two adjustable lugs
    An earthing tail must be fitted between a socket-outlet and a back box having two adjustable lugs, such as the box shown in Fig 2. The need for this has been demonstrated where socket-outlets have suffered overheating and burning around the fixing holes due to a line-to-earth fault in metal boxes which had not been provided with an earthing tail. Because the adjustable lugs had become corroded, they presented a high resistance to the earth fault current, and consequently the circuit overcurrent protective device did not operate within the maximum time permitted by BS 7671. This resulted in a risk of electric shock as well as the thermal effects already mentioned.

    Fig 1



    [/TD]
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    [/TD]
    [/TR]
    [TR]
    [TD]
    [​IMG][/TD]
    [TD]
    Fig 2


    2.3 Metallic box with one fixed and one adjustable lug
    Care must be exercised when installing back boxes having one fixed lug and one adjustable lug, as shown in Fig 3, because some socket-outlets have only one earthing strap and eyelet. It must be ensured that the earthing eyelet is located at the fixed lug position, otherwise an earthing tail must be provided.
    Photograph courtesy of Legrand Electric Ltd.

    Fig 3



    3. Where the cpc is formed by metallic conduit, trunking or ducting, or the metal sheath or armour of a cable
    Regulation 543.2.7 of BS 7671 requires an earthing tail to be fitted where the cpc associated with the circuit wiring from the distribution board to the socket-outlet is formed by metallic conduit, trunking or ducting, or the metal sheath or armour of a cable. The earthing tail must connect the earthing terminal of the socket-outlet to the earthing terminal incorporated in the associated back box (see Fig 4).

    [/TD]
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    [/TD]
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    [​IMG][/TD]
    [TD]An ‘earthing tail’ is required where the protective conductor is formed by metallic conduit, trunking or ducting, or the metal sheath and/or armour of a cable

    Fig 4

    The purpose of the earthing tail is not to earth the back box but to earth the socket-outlet (by connecting it to the back box).
    The earthing of the back box itself is reliant upon the metallic conduit, trunking, ducting, or metal sheath or armour of a cable, forming the cpc. The requirements of BS 7671 relating to the use of such parts of a wiring system as a cpc are discussed in Topic P157-7.

    [/TD]
    [/TR]
    [/TABLE]
     
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  5. steve snakeman
    Online

    steve snakeman Guest

    Thankyou very much.Oh and he did nothing as only a report was requested,personally anything I categorised as a class one I would not walk away from. :)
     
    • Like Like x 1
  6. telectrix
    Offline

    telectrix Scouser and Proud of It Respected Member

    Location:
    cheshire/staffordshire
    Business Name:
    Telectrix
    trust the esc to turn a simple 4 line explanation into an essay
     
    • Like Like x 5
  7. steve snakeman
    Online

    steve snakeman Guest

    just togive you a laugh I have been looking through his condition report and have just noticed this.....Hole in the wall where an extractor fan used to be ....requires further investigation?? That made me laugh.
     
  8. trev
    Offline

    trev Regular EF Member

    Maybe he didn't have time to look through the hole
     
    • Like Like x 5
  9. hermetic
    Offline

    hermetic Regular EF Member

    Location:
    East Yorkshire
    very interesting, a regulation that condones skimping, can anyone tell me what is achieved by not fitting a fly lead, apart from the saving of 100mm of copper and a bit of sleeving. I am really glad that I am not working day to day in domestic any more!
     
  10. aaelectric
    Offline

    aaelectric Regular EF Member

    So isit required or not and what regs states it
     
  11. spinlondon
    Offline

    spinlondon Forum Mentor

    Location:
    Harlow Essex
    Perhaps he's going to get the Police to look into it?
     
    • Like Like x 2
  12. Geoffsd
    Online

    Geoffsd Guest


    No.

    You cannot prove a negative.
     
  13. D Skelton
    Offline

    D Skelton Fidei Defensor Forum Mentor

    Location:
    Canada
    About 3 mins labour per socket.

    "Not much" I hear you say but when you're second fixing 30 dso's on a rewire, that's still two hours you could be spending on something else!
     
    • Like Like x 1
  14. albi1001
    Online

    albi1001 Guest

    If ever you are unsure about anything regarding earth connections always fit more than less. I have personally seen someone crossbond radiators and sinks in bathrooms when they know that the pipes under the floor are PVC fed. ****ing madness!!! I personally as a joke charged one of these radiators with a wind up generated high voltage (MEGA) and got a teenager to touch the radiator which was cross bonded (to pvc supply pipes). He jumped as high as the red bull he had been drinking prior to shock and seemed alert and even more keen & inquizitive to learn about electricity after his short sharp shock. Once i explained about the 17th edition regulations he said "well that clearly does not make any sense then, i'm back on my X-box". I personally cover everything i use in bathrooms with SELV and RCD or RCBO. "radiators do not need bonding but cross-bonding to all copper or metal fed piping & metal bathroom furniture"
    Contact [email protected] for any chats...
     
  15. malcolmsanford
    Offline

    malcolmsanford Electrician's Arms

    543.2.7

    " Where the protective conductor is formed by METAL conduit, trunking, or ducting or the metal sheath and/or armour of a cable, the earthing terminal of each accessory shall be connected by a separate protective conductor to an earthing terminal incorporated in the associated box or other enclosure"

    I underlined and made bold the only change from the original BS 7671.

    So as to the regs the only time you need a fly lead in a box is when your using containment/exposed conductive part as protective conductor.

    So though all the bodies ESC/NICEIC/GN notes advise that if there is not a fixed lug you should fit a fly lead on a T+E back box, it does not actually say so in the regs, and so if you are doing an EICR and found a non fixed lug box without a fly lead, should you code it ...............it is after all guides and advice say you should?

    What would you do, and if you code it what would be the code, and why, and to what regulation.
     
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