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Thread: To what point must would you test

  1. #1
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    To what point must would you test

    I have recently tested an installation, a baggage handling system. I tested from the Local mains (fed from substations) to each control panel for the baggage handling system. The control panel has an isolator and from that isolator it feeds busbars in the panel from which the breakers for the various parts of the baggage handling system are are controlled. The PLC controls contractors which obviously control various parts of the systems motors etc etc.

    Now because "SANS 10142 does not intend to cover LV control circuits of machinery or system components that are external circuits between separately installed parts of the machinery or system components" I'm sure the out going circuits from the control panel (motor circuits) and the control cabling is not essentially covered by SANS 10142 and therefore can't be covered by a COC.

    But I see in "OCCUPATIONAL HEALTH AND SAFETY ACT, 1993
    ELECTRICAL INSTALLATION REGULATIONS" that the definition of an electrical installation is-

    "electrical installation" means any machinery, in or on any premises, used
    for the transmission of electricity from a point of control to a point of
    consumption anywhere on the premises, including any article forming part of
    such an electrical installation irrespective of whether or not it is part of the
    electrical circuit, but excluding
    (a) any machinery of the supplier related to the supply of electricity on the
    premises;
    (b) any machinery which transmits electrical energy in communication,
    control circuits, television or radio circuits;
    (e) an electrical installation on a vehicle, vessel, train or aircraft; and
    (d) control circuits of 50 V or less between different parts of machinery or
    system components, forming a unit, that are separately installed and
    derived from an independent source or an isolating transformer;

    Contradiction?

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    No seems pretty consistent to me:

    "electrical installation" means any machinery.... but excluding

    (d) control circuits of 50 V or less between different parts of machinery or
    system components, forming a unit, that are separately installed and
    derived from an independent source or an isolating transformer; "

  3. #3
    Diamond Member AndyD's Avatar
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    Quote Originally Posted by skatingsparks View Post
    But I see in "OCCUPATIONAL HEALTH AND SAFETY ACT, 1993
    ELECTRICAL INSTALLATION REGULATIONS" that the definition of an electrical installation is-

    "electrical installation" means any machinery, in or on any premises, used
    for the transmission of electricity from a point of control to a point of
    consumption anywhere on the premises, including any article forming part of
    such an electrical installation
    This is that whole point of control, point of outlet and point of consumption definition thing.

    6.16.1.1 Fixed appliances do not form part of the electrical installation
    other than their positioning in relation to the supply and the wiring carried
    out between different parts of the appliances.
    After digging though the regs I'm not sure there's a contradiction, 6.16.1.1 includes the motor supply cables from a control panel in the CoC. I'm not sure why on earth they'd want to do this though, there's so many other design perameters in play with these circuits that can't possibly be the domain of the standard installation regs such as EMI/EMC compliance etc.
    Last edited by AndyD; 12-Aug-14 at 01:24 AM.
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    I took it that if something is controlled by a control panel only the power up to the isolator in/on the control panel is part of the COC. My old example is the baggage handling system. There is a supply to the panel and then from the panel numerous motor banks which are controlled by a PLC via a contactors. Now those motors are changed almost on a daily basis as part of maintenance. I tested the supply up to panel isolator and all was good. I take the motors to be part of the machine. A big machine but is that machine still to be covered by SANS 10142 in a COC. If the motor is changed on the machine should another COC be done?

    Another example. A supply to an isolator and connected to an isolator is a conrtol panel for 2 large geysers. The supply to the geysers is from 2 contractors, one for each geyser, controlled by thermostats within the 2 geyser. Should the COC cover those control systems? Or is that those controls are part of the fixed appliance which is the geyser? I look at the COC, number of geyser points? One. The geyser supply to the 2 geysers from one control panel fed from one islolator, right? I only sign up to teh isolator, right? I mean what if teh geyser installer does something silly (there were a total of 6 elements in that geyser, only 2 were connected. What happens when they connect more because water is being used faster for some reason and the cables in the control system melt?

    6.16.1.1 Fixed appliances do not form part of the electrical installation
    other than their positioning in relation to the supply and the wiring carried
    out between different parts of the appliances.

    So is it a fail if a cooker comes with a skinny 1.5mm 3 core and its connected to a isolator backed up with a 30 or 40 amp cable on a 6mm. I know its not right but what control do we have over what people connect to our isolators.

    I have just been testing up to isolators of machines (no matter the size)

    Right or wrong.

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