internal stud wall with 100mm rockwool acoustic slab

[redtop]

want to use rockwool acoustic slab to help soundproof the internal timber stud walls. Does this mean the cables dropping to light switches and sockets will need derating. Must be a really common issue, how don you get round it?

[ProDave]

Make sure the cables are on the surface of the insulation slab, i.e between the insulation and the PB.  It is only cables IN insulation that have to be derated, not cables ON insulation.

[redtop]

10 hours ago, ProDave said:

Make sure the cables are on the surface of the insulation slab, i.e between the insulation and the PB.  It is only cables IN insulation that have to be derated, not cables ON insulation.

Top plan, and I only need to worry about being 50mm deep if I am outside of the safe zones? FYI I am running 1st fix, sparky hss given me instructions but just checking a couple of bits. He will then come and check before we pb. 

[ProDave]

You should not be running outside safe zones.

 

The 50mm deep thing is for RCD protection.  In some cases if a cable is more than 50mm deep (and in a safe zone) you might be able to get away without RCD protection to that cable. But why would you want to?

[redtop]

Just now, ProDave said:

You should not be running outside safe zones.

 

The 50mm deep thing is for RCD protection.  In some cases if a cable is more than 50mm deep (and in a safe zone) you might be able to get away without RCD protection to that cable. But why would you want to?

yes, new installation so all circuits are rcbo protected

[TonyT]

put a metal plate over the hole to save any future issues.

safe plates are cheap, removing plasterboard to fix cables not so.

 

https://www.screwfix.com/p/sabrefix-protecta-safe-plate-galvanised-90mm-x-45mm-20-pack/30038?tc=MC9&ds_kid=92700058021678484&ds_rl=1249407&ds_rl=1241687&ds_rl=1245250&ds_rl=1245250&gclid=EAIaIQobChMIvveM1ZKM7QIVDO7tCh2YvgwYEAQYAyABEgL6WfD_BwE&gclsrc=aw.ds

 

 

[Onoff]

Depending on how many sockets you can go horizontal rather than dropping/back up/across, drilling through the studs between sockets. 

[ProDave]

20 minutes ago, Onoff said:

Depending on how many sockets you can go horizontal rather than dropping/back up/across, drilling through the studs between sockets. 

Always my perfered method, apart from anything else, the cable is there so you can easily add extra sockets anywhere else you want later on.

 

It is surprising how many people think you are not allowed to do that.