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The maximum permissible disconnection time is 0.4 s in TN system. Why and from where this value (0.4 s) is obtained?

Former Community Member
Former Community Member
The maximum permissible disconnection time in in the event of a short circuit between a phase conductor and a body or protective conductor or a protective-neutral conductor is 0.4 s in TN system. Does anybody know this value (0.4 s) obtains from where? How this value is obtained?
Parents
  • Former Community Member
    0 Former Community Member
    Or simply use:


    Vtouch = Ifault x R2


    Where R2 is the resistance of the CPC within the installation, if the installation is bonded  - and is the whole resistance of the earth path if not bonded


    That should illuminate admirably why bonding in a TT system is a jolly good idea


    Regards


    OMS
Reply
  • Former Community Member
    0 Former Community Member
    Or simply use:


    Vtouch = Ifault x R2


    Where R2 is the resistance of the CPC within the installation, if the installation is bonded  - and is the whole resistance of the earth path if not bonded


    That should illuminate admirably why bonding in a TT system is a jolly good idea


    Regards


    OMS
Children
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