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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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  • Former Community Member
    0 Former Community Member

    Sparkingchip:

    Highest voltage and current it has to withstand after a failure of the FELV transformer has put the primary circuit voltage onto the secondary circuit along the the primary circuit fault current.


    The secondary circuit could have 240 volts and several hundred amps to deal with if the transformer insulation breaks down livening up all the earthed metalwork.


    Andy 




    Andy the question was 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.


    In regards to your above statement this structural steel work may be located inside an HV switchroom where the highest voltage to withstand may be thousands of volts however this has no bearing in regards to the conclusion that we arrive at as we summized that the equipotential bonding cable did not meet the criteria to be classed as SELV, PELV, FELV, RLV, LV, MV on that basis that the equipotential bonding cable did not form part of a system that had a designated voltage.

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  • Former Community Member
    0 Former Community Member

    Sparkingchip:

    Highest voltage and current it has to withstand after a failure of the FELV transformer has put the primary circuit voltage onto the secondary circuit along the the primary circuit fault current.


    The secondary circuit could have 240 volts and several hundred amps to deal with if the transformer insulation breaks down livening up all the earthed metalwork.


    Andy 




    Andy the question was 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.


    In regards to your above statement this structural steel work may be located inside an HV switchroom where the highest voltage to withstand may be thousands of volts however this has no bearing in regards to the conclusion that we arrive at as we summized that the equipotential bonding cable did not meet the criteria to be classed as SELV, PELV, FELV, RLV, LV, MV on that basis that the equipotential bonding cable did not form part of a system that had a designated voltage.

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