Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 52 replies
  • Subscribers 30 subscribers
  • Views 10937 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

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 ?
Parents
  • 0

    Mike M:

    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 ?




    No, green-and-yellow cables are protective conductors.


    As others have said, protective conductors can carry hazardous voltages and currents.


    Under normal circumstances, when connected properly in the electrical installation, they are considered safe to touch, at least in dry conditions, as they are connected to exposed-conductive-parts or extraneous-conductive-parts.


    However, once a protective conductor is disconnected at one end, it must be considered as hazardous to touch, and may in fact be carrying low voltage (LV) hazardous voltages and currents, and is therefore definitely never ELV.


    In HV installations, a different set of criteria exists, and in fact under fault conditions, earth conductors may even when connected be LV (or occasionally higher for short periods).

Reply
  • 0

    Mike M:

    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 ?




    No, green-and-yellow cables are protective conductors.


    As others have said, protective conductors can carry hazardous voltages and currents.


    Under normal circumstances, when connected properly in the electrical installation, they are considered safe to touch, at least in dry conditions, as they are connected to exposed-conductive-parts or extraneous-conductive-parts.


    However, once a protective conductor is disconnected at one end, it must be considered as hazardous to touch, and may in fact be carrying low voltage (LV) hazardous voltages and currents, and is therefore definitely never ELV.


    In HV installations, a different set of criteria exists, and in fact under fault conditions, earth conductors may even when connected be LV (or occasionally higher for short periods).

Children
No Data

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines