The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

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 12 replies
  • Subscribers 31 subscribers
  • Views 1608 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

Sub Main in Notched Joists. Your Opinion Please.

Zoomup
Here we have a 16.00mmm2 T&E cable installed many years ago in a house, and it supplies a recently renewed consumer unit in an annexe. The cable runs under the first floor boards in notched  wooden joists. The boards are about 15mm thick. There is no mechanical protection apart from the wooden boards. The cable runs centrally to the floor boards  in the notched joists.


What is your opinion about leaving the cable where it is? It is backed up by a 60 Amp fuse in a switch fuse. There is no R.C.D. protection for the sub-main cable.


Z.


  • 0
    Chris Pearson:
    Zoomup:

    I am not inclined to reduce the strength of the  wooden joist any more Chris by drilling. The cable is large, about the width of a man's thumb.


    As I am sure you know, the French translation of "an inch" is "un pouce", which is also their word for a thumb. But that is length, not breadth. I have just measured my own thumb with my super-accurate Mitutoyo callipers and it is exactly, if not precisely, 1/2" wide.


    I actually would not worry about drilling 1/2" holes, but it is hard work and gives me blisters. I agree - stick with what you have. ?




    Chris, the cable is 16mm2 T&E and a lot wider than 1/2 inch. My thumbs are nearer an inch wide. The floor boards are up for other work not an E.I.C.R. production. To renew the cable will be a lot of work. I think that I will leave it alone, but the B.E.S.A. box covers are a good idea.  I will mark the floor boards in black marker pen to advise of cables below. The owner is a developer and pretty familiar with building work. He lifted the boards so knows the situation. P.S. I would not like to pull 16mm2 T&E cable through holes in wooden joists anyway. Too difficult.


    Z.


     


  • 0
    Zoomup:

    P.S. I would not like to pull 16mm2 T&E cable through holes in wooden joists anyway. Too difficult.


    Far too difficult for my dainty hands! Now you know why it is in notches.


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