Metal or Dry lining back boxes

[Knickam]

Building a new house and on the external walls I will have a 35
mm internal cavity to run cables pipes etc.

Over the years have had the odd problem with the dry lining
back boxes coming loose due to the drywall breaking up.

What I was thinking is we could screw 35mm metal back boxes in place
with plastic conduit before the drywall goes on carefully marking
the locations.

I know there is extra time and cost involved doing this but any
comments from seasoned sparks would be welcome and views on
if it is a worthwhile exercise.

 

[PrenticeBoyofDerry]

100% go with metal back boxes over dry-lined ones.
35mm is a good size, as it will allow you to use flatplate for socket-outlets if you decide to use them one day in the future.

 

[1john]

excellent way of doing it

 

[333rocky333]

Yes also.

Plus the bonus of level adjustment for the sockets and better finish round the socket edges i think..

 

[ban-all-sheds]

plastic conduit.

Even better - use steel conduit, then you can avoid RCDs on lighting, cooker etc circuits.

 

[mfarrow]

Even better - use steel conduit.

Or even cheaper and easier still, SWA.

 

[ricicle]

Even better - use steel conduit.

Or even cheaper and easier still, SWA.

Although SWA has it's place in underground installs and industrial I would not use it buried in household walls. There is still a possibility that the drill could penetrate between the wire armour leaving you with a very difficult repair. You would have to drill some to penetrate steel conduit with a masonary bit.

 

[mfarrow]

There is still a possibility that the drill could penetrate between the wire armour leaving you with a very difficult repair.

Which is also true of twin & earth. Does that mean you've always put every cable in conduit when running behind a wall?

 

[Knickam]

Thanks for the comments,

I know steel conduit would be quite time consuming to
put in so will probably go plastic with RCBO protection,
But i will see what the spark thinks.