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Extra Low Voltage (ELV)

Former Community Member
Former Community Member
Guys,


BS7671:2018 is classing cables extra low voltage (ELV) as an operating voltage not exceeding 50Vac or 120V ripple-free dc.


BS7671 goes on to further categorize ELV cables into SELV, PELV, FELV.


For single core green/yellow insulated equipotential bonding cables lets say originating from an earth bar and bonding some structural steel work, are these classed as FELV under BS7671:2018 ?
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    Mike M:

    Andy thanks for the response.


    BS7671:2018 states


    "Voltage, nominal. Voltage by which an installation (or part of an installation) is designated. The following ranges

    of nominal voltage (rms values for AC) are defined:"

    – Extra-low. Not exceeding 50 V AC or 120 V ripple-free DC, whether between conductors or to Earth.

    – Low. Exceeding extra-low voltage but not exceeding 1000 V AC or 1500 V DC between conductors, or

    600 V AC or 900 V DC between conductors and Earth.

    – High. Normally exceeding low voltage.


    For the protective conductor not to be categorized into one of these groups it would mean that the protective conductor is not part of a system that has a designated nominated voltage. If that is the case then I agree however I am unable to find something to back this up in BS7671, perhaps this is further defined somewhere else ?




    The protective conductor is designed for the highest voltage and fault current that it is anticipated it will have to deal with, so what is the answer to your question?


     

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  • 0

    Mike M:

    Andy thanks for the response.


    BS7671:2018 states


    "Voltage, nominal. Voltage by which an installation (or part of an installation) is designated. The following ranges

    of nominal voltage (rms values for AC) are defined:"

    – Extra-low. Not exceeding 50 V AC or 120 V ripple-free DC, whether between conductors or to Earth.

    – Low. Exceeding extra-low voltage but not exceeding 1000 V AC or 1500 V DC between conductors, or

    600 V AC or 900 V DC between conductors and Earth.

    – High. Normally exceeding low voltage.


    For the protective conductor not to be categorized into one of these groups it would mean that the protective conductor is not part of a system that has a designated nominated voltage. If that is the case then I agree however I am unable to find something to back this up in BS7671, perhaps this is further defined somewhere else ?




    The protective conductor is designed for the highest voltage and fault current that it is anticipated it will have to deal with, so what is the answer to your question?


     

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