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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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    So the circuit protective conductor or any other protective conductor has to be capable of withstanding the voltage and current that may be placed on it, which in the case of a FELV circuit is generally 240 volts, even though the circuit is rated at say 24 Vdc.



    I'm not sure I understand the concept of a protective conductor being able to "withstand" a certain voltage - given that generally there's no requirement for protective conductors (or they parts they connect) to be insulated. Live conductors need insulation of course (including from the protective conductor or exposed-conductive-parts) - and in the case of FELV that might need to be according to the voltage of the primary circuit rather than the secondary - but I'm not aware of any similar requirement for FELV c.p.c.s.


       - Andy,
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  • 0

    So the circuit protective conductor or any other protective conductor has to be capable of withstanding the voltage and current that may be placed on it, which in the case of a FELV circuit is generally 240 volts, even though the circuit is rated at say 24 Vdc.



    I'm not sure I understand the concept of a protective conductor being able to "withstand" a certain voltage - given that generally there's no requirement for protective conductors (or they parts they connect) to be insulated. Live conductors need insulation of course (including from the protective conductor or exposed-conductive-parts) - and in the case of FELV that might need to be according to the voltage of the primary circuit rather than the secondary - but I'm not aware of any similar requirement for FELV c.p.c.s.


       - Andy,
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