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Thread: Cabtyre vs Twin + E for fixed extension cords

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    Cabtyre vs Twin + E for fixed extension cords

    Dear forum,
    Have been lurking for a while, but this is my first post, so please accept my apologies if this is the wrong place to ask these questions.

    I admit, I am a DIY person and not a qualified electrician.

    My quandary.
    I requested an inspection of my home electrical installation (house built in the 40's, but significantly altered since then, including the electrics) and some of the issues found were as follows.

    Cabtyre extension leads fed from an internal plug supplying a booster-pump and grey-water installation. The cable was protected with a PVC pipe outside and secured to the wall and connected to a protected plug box 1m from the installation.

    CoC was denied as cabtyre may not be used for a fixed installation. So this was an extension lead beyond the point of consumption and I replaced said cable with Twin + E (1,5 mm2). I am awaiting the delivery of 16A fused plugtops for this.

    Original company refused to "sign-off" or re-inspect (I expected this), so approached company B.
    Company B now refused to issue CoC as I used undersized Twin + E and wired into a plugtop. Inspector stated it should be cabtyre if wired from a plugtop.

    I am now very confused and am seeking clarification on the use of cabtyre and twin + E when used as an extension lead for a fixed installation.

    Thanks for a very informative forum

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    Hi

    We use clause 6.16.1.10 , pasted below in similar circumstances to what you describe above.

    If the twin and earth or cabtyre is clipped and made to look part of the installation , then it is part of the installation and needs to comply.
    We would use 2,5sqmm and connect it to the plug circuit and not through a plug top.

    6.16.1.10 The wiring between different parts of a fixed appliance that are
    installed separately is part of the fixed installation, even where it is supplied
    from a socket-outlet, unless such wiring is less than 3 m in length.
    Such wiring shall be protected by separate overload protection unless its
    current-carrying capacity is such that the circuit protection of the socketoutlet
    circuit will provide protection or that part of the appliance has built-in
    thermal overload protection.
    NOTE Where the length of wiring exceeds 3 m, the impedance and the functioning of
    the protective devices need to be considered to satisfy the overcurrent protection
    requirements in this part of SANS 10142.

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    Quote Originally Posted by GCE View Post
    Hi

    We use clause 6.16.1.10 , pasted below in similar circumstances to what you describe above.

    If the twin and earth or cabtyre is clipped and made to look part of the installation , then it is part of the installation and needs to comply.
    We would use 2,5sqmm and connect it to the plug circuit and not through a plug top.

    6.16.1.10 The wiring between different parts of a fixed appliance that are
    installed separately is part of the fixed installation, even where it is supplied
    from a socket-outlet, unless such wiring is less than 3 m in length.
    Such wiring shall be protected by separate overload protection unless its
    current-carrying capacity is such that the circuit protection of the socketoutlet
    circuit will provide protection or that part of the appliance has built-in
    thermal overload protection.
    NOTE Where the length of wiring exceeds 3 m, the impedance and the functioning of
    the protective devices need to be considered to satisfy the overcurrent protection
    requirements in this part of SANS 10142.
    Thanks GCE.
    Questions:
    So can one use cabtyre from a plugtop (with overload protection) in such a fixed extension lead?
    Is there a regulation that prevents you wiring twin + E from a plugtop?
    Keep safe

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    I dont know of any plug top that has overload protection besides the old 13Amp square pin type which is now illegal to use.

    T&E in a plug top is a DIY solution and if the cord is over 3m and fixed to the installation it needs to be done correctly .

    The T&E is solid copper and will eventually break , and the eventually will be a short process.

    The regulations are a minimal standard and common sense also needs to prevail.

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    Thanks GCE,
    I agree that T&E into a plugtop is far from ideal, but the electricians that installed the floor heating did exactly that; and the inspector stated that cabtyre was not allowed in a fixed installation, even if it's essentially an extension cord. That leaves me no choice but to use inflexible wire from a plugtop.

    However, digging a bit deeper, I came across the draft SAN 10142-1 regs and this stated:

    6.1.11 Where flexible cords are used as part of the electrical installation, the
    selection, installation and colour identification (see 6.3.3) shall be done in
    accordance with this part of the standard.
    6.1.12 Where flexible cords are used, the strands of the conductors shall be
    mechanically protected with ferrules to prevent the strands from being cut off
    in terminations.

    I am not certain that these new regs were implemented, but if they were I will replace the T&E with suitable cabtyre. (If you have access to the 2020 published version, I would be grateful if you could confirm this)

    CrabTree evidently sell a fused 16A 3 pin plugtop (https://www.crabtreeonline.co.za/col...-pin-16a-fused)

    Regards and keep safe.

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