Cabling Behind Rock Wool Insulation in new Ceiling in Room Below Loft Conversion
Ask questions and find answers to many subjects relating to electrics and electrical work

3 posts   •   Page 1 of 1
Holywood
Apprentice
Apprentice
Posts: 13
Joined: Tue Oct 16, 2007 7:29 pm

Cabling Behind Rock Wool Insulation in new Ceiling in Room Below Loft Conversion

by Holywood » Tue Mar 10, 2015 1:45 pm

As I need to put rock wool insulation in a new ceiling in the room below a loft conversion could anyone tell me please if it is sufficient to run the cabling in the space between the insulation and the floor above.

As the joists are engineered timber of 12inches in height and the insulation is only 50mm in depth there appears to be plenty of room to ensure that the cables aren't touching it.

Also should the cabling be on the ceiling side or the floor (above) side of the insulation please? Given the depth of the joists is it right that the cabling won't need to be put in conduit?

Thanks for any help.

ericmark
Project Manager
Project Manager
Posts: 2850
Joined: Fri Oct 02, 2009 9:49 pm
Location: Llanfair Caereinion, Mid Wales.

Re: Cabling Behind Rock Wool Insulation in new Ceiling in Room Below Loft Conversion

by ericmark » Wed Mar 11, 2015 9:14 am

Cable should be 50mm from either top or bottom surface to avoid any nails etc used in the future. When correctly cleated to beams the beams themselves will help remove the heat the regulations tell us a 2.5mm sq cable fitted to Reference Method 100# (above a plasterboard ceiling covered by thermal insulation not exceeding 100 mm in thickness) is rated at 21 amps and the limit for cable used in a ring final is 20 amps so it is within the limit by 1 amp.

http://www.doncastercables.com/technical-help/4 shows the tables but can't find any of the pictures on line.

Holywood
Apprentice
Apprentice
Posts: 13
Joined: Tue Oct 16, 2007 7:29 pm

Re: Cabling Behind Rock Wool Insulation in new Ceiling in Room Below Loft Conversion

by Holywood » Fri Mar 13, 2015 8:09 pm

Thanks Eric for your response which is v helpful.

Regards

3 posts   •   Page 1 of 1
It is currently Sat Mar 02, 2024 10:58 pm