For what does PELV require protective conductor? And also what is differences between PELV and FELV?

I'm not sure a PELV circuit requires a protective conductor at all - it may have one if you want (e.g. for functional reasons), but as far as I can see it's not actually required by regs.


PELV circuits (unlike SELV ones) may be connected to Earth - but that connection need not involve a protective earth conductor - as it's not required for protection against electric shock as far as the PELV circuit is concerned.

There are situation where PELV systems require a protective conductor to connect exposed-conductive-parts, see 414.4.5. Arguably, this would necessarily be separate to the Neutral (earthed conductor), see notes to Figures 9H and 9I in Appendix 9, regardless of the voltage concerned.

 Any old means of earthing, or just a potential for fortuitous contact with earth (say lack of insulation on one pole in an earthy environment), would be enough to make a circuit PELV rather than SELV.

Not where the voltage of the PELV system does not exceeds 25 V AC or 60 V DC, because the lack of insulation on one pole implies that basic protection is not present, and if the voltage exceeds 25 V AC / 60 V DC then basic protection is required or the conductor installed in an earthed metal enclosure or containment system, see 414.4.5. Alternatively, perhaps it becomes a PEN or PEM conductor in those conditions, again where the voltage exceeds 25 V AC / 60 V DC?



And just to reiterate, where earthing is required for functional purposes, it may well be necessary for this to be a separate conductor (or "screen"), simply because of the job it's doing (e.g. EMC) - basically, not always best to shove the "noise" down the circuit conductor.

I'm not sure a PELV circuit requires a protective conductor at all - it may have one if you want (e.g. for functional reasons), but as far as I can see it's not actually required by regs.


PELV circuits (unlike SELV ones) may be connected to Earth - but that connection need not involve a protective earth conductor - as it's not required for protection against electric shock as far as the PELV circuit is concerned.

There are situation where PELV systems require a protective conductor to connect exposed-conductive-parts, see 414.4.5. Arguably, this would necessarily be separate to the Neutral (earthed conductor), see notes to Figures 9H and 9I in Appendix 9, regardless of the voltage concerned.

 Any old means of earthing, or just a potential for fortuitous contact with earth (say lack of insulation on one pole in an earthy environment), would be enough to make a circuit PELV rather than SELV.

Not where the voltage of the PELV system does not exceeds 25 V AC or 60 V DC, because the lack of insulation on one pole implies that basic protection is not present, and if the voltage exceeds 25 V AC / 60 V DC then basic protection is required or the conductor installed in an earthed metal enclosure or containment system, see 414.4.5. Alternatively, perhaps it becomes a PEN or PEM conductor in those conditions, again where the voltage exceeds 25 V AC / 60 V DC?



And just to reiterate, where earthing is required for functional purposes, it may well be necessary for this to be a separate conductor (or "screen"), simply because of the job it's doing (e.g. EMC) - basically, not always best to shove the "noise" down the circuit conductor.