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 15 replies
  • Subscribers 32 subscribers
  • Views 2617 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

table 41.1 max. disconn. times and the extra notes

psychicwarrior
good day folks


"Where in TT systems the disconnection is achieved by an overcurrent protective device and the protective equipotential bonding is connected with all extraneous-conductive-parts within the installation in accordance with Regulation 411.3.1.2, the maximum disconnection times applicable to TN systems may be used."


Does this [also] imply that where protective equipotential bonding is not needed, then TN times can be used ?


And what reasons might there be for no similar relaxation of effectively 411.3.2.4 to 411.3.2.3  (1s to 5s  for other circuits not covered in 411.3.2.2 and in the light of the above extracted note to 411.3.2.2 Reg ) ?


Regards

Habs


Parents
  • 0
    Just in case it was not obvious, my post was not about using RCD or not :-)


    It was the 'notes' (extract in first post) I was musing about; presumably made just in the [rare] occasion the TT earth is extremely low that then the TT times can be relaxed to TN times if bonding is in place - possibly impled too, to also be fine to relax where bonding not required - but where that relaxation is applicable, seemingly there is no provision to relax to TN times for other circuits not covered in 411.3.2.2  ...  I was wondering why.


Reply
  • 0
    Just in case it was not obvious, my post was not about using RCD or not :-)


    It was the 'notes' (extract in first post) I was musing about; presumably made just in the [rare] occasion the TT earth is extremely low that then the TT times can be relaxed to TN times if bonding is in place - possibly impled too, to also be fine to relax where bonding not required - but where that relaxation is applicable, seemingly there is no provision to relax to TN times for other circuits not covered in 411.3.2.2  ...  I was wondering why.


Children
No Data

Community Rules & Guidelines