Wed, 17 Jun 2026 14:12:57 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73636#Comment_73636 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73636#Comment_73636 Fri, 05 Feb 2010 14:51:55 +0000 marsaday
Can i run my lighting cable in the rafter? It is 100mm and will have 75mm of celotex in there. then there is a 25mm breather gap and then you have the bare slate. So is it ok to run the cable in this 25mm breather channel, basically up against the slate?

next i plan on running the power cable over the current ceiling joists. Above this will be laid a new 8" joisted floor. insulation will go between these joists. Is there anything i need to think of in terms of protecting the cables? The insulation will be on top of the new ring main and so will this pose a problem? Alternatively i will lay the new ring main on top of the insulation, but i deally i would like it to go down below the new floor so out of the way.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73638#Comment_73638 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73638#Comment_73638 Fri, 05 Feb 2010 15:22:29 +0000 CWatters
The maximium load a wire can carry changes if it's burried in insulation. May not be a problem but depends on the load. I believe they must be burried a minimium depth (50mm?) from the surface of the plasterboard (to stop nail damage).

There are safe area where cables can and can't be run in walls. They should go vertically up or down to sockets never at funny angles. I believe there are also safe area in the corners of rooms and ??

Technically you don't need an electrician if you are making a Building Control Application. The official rules say the BCO is meant to test everything you DIY install and isn't meant to make you pay for an electrician to get it tested. It's all meant to be covered by the fee you paid for Building Control Approval - John Prescott said so in writing to planning departments way back... but it hasn't stopped many BCO insisting though.

Has he said you need a new breaker in the consumer unit or if you can tap off an existing ring?

Don't forget wire for the smoke alarm?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73641#Comment_73641 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73641#Comment_73641 Fri, 05 Feb 2010 15:44:57 +0000 marsaday
i have had a good idea! if i remove the 100mm insulation between the ceiling joists i can then lay the cabling on top of the ceiling. Above this will be a new 8" floor filled with 200mm insulation. so the wiring will be sat below all of this.

i will be using the sparky to help me and will be doing lots with him.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73642#Comment_73642 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73642#Comment_73642 Fri, 05 Feb 2010 16:13:23 +0000 jamesingram Make sure the pvc cable is protected from the PUR board , recent research quoted showed problems with cable degrading if in contact ( EPS and pvc cable problems have been known for a while )
Cables should be only routed in the prescribed zones unless mechanicially protectd and at a depth >50mm and avoid being covered by insulation where practicial or I.t. down rated with reference to BS7671:2008
No reason I'm aware of why you can run them in the area suggested on the rafters.
Why would you remove insulation and then pay to put more back , I think regs require 30minute ceiling ? so skimmmed 12.5 with 100mm rockwool on chicken wire should be fine. run your cables on the sides of the new joists >50mm below the floor .]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73643#Comment_73643 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73643#Comment_73643 Fri, 05 Feb 2010 16:24:47 +0000 marsaday
as you say the sparky will advise properly, but i am doing some of my own research as i like to know what is what.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73650#Comment_73650 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73650#Comment_73650 Fri, 05 Feb 2010 18:22:12 +0000 aa44 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73916#Comment_73916 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=73916#Comment_73916 Mon, 08 Feb 2010 21:16:24 +0000 batkinson The reason why aa44 suggests that many new builds dont comply with the standards is one of the main reasons wiring was brought into building regulations but unfortunatly the CLG then came up with the competant persons schemes!!!!!!!!!!]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=74147#Comment_74147 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=5302&Focus=74147#Comment_74147 Wed, 10 Feb 2010 22:51:03 +0000 jamesingram i pretty sure thats not the case. Importantly cables must be run in permitted zones
check 522.6]]>