Cabling through Studwork with Kingspan

[meb97me]

Hi

I've had a search but not found anything that answers my question. I'm hoping one of you kind folk might be able to help me.

I've had a small wooden workshop built that's timber clad on the outside and will be ply lined on the inside. I'm planning on fitting 100mm foilbacked Kinspan sandwiched between the studwork as a means of insulation.

My question is what to do about the wire routing through the studwork. As the kinspan is the same depth as the studs there isn't a service void. My initial plan was to drill holes through the vertical studs and feed the wires through that way, but obviously the kinspan will be slap bang in the way. Is it acceptable to keep the centre holes through the studs and then have the cables run across the front or back of the insulation then dip back through the hole and then back to the surface again of the next void?

I have seen a vid on an american site where they notch out a groove on the surfae of the studs with a circular saw/chisel and run the cable through there but i'm abit weary of running the cable on the surface of the studwork for fear of forgeting exactly where it is and sticking a screw/nail through it once the plyboards are covering it!!

Many Thanks

 

[ban-all-sheds]

If it's a workshop why not run the cables on the surface, in conduit?

 

[meb97me]

i suppose its an option but i'd really prefer to keep it all hidden away if possible

 

[ban-all-sheds]

As the kinspan is the same depth as the studs there isn't a service void.

Use thinner insulation?

Fix 10mm battens to the studs to create a void?

Is it acceptable to keep the centre holes through the studs and then have the cables run across the front or back of the insulation then dip back through the hole and then back to the surface again of the next void?

Won't that mean removing bits of insulation?

i'm abit weary of running the cable on the surface of the studwork for fear of forgeting exactly where it is and sticking a screw/nail through it once the plyboards are covering it!!

That won't happen, as long as you follow the rules and remember that you followed them.

• http://www.voltimum.co.uk/files/gb/attachments/niu/l/attachments/c5-43.pdf
• http://web.archive.org/web/20061110111450/http://www.niceic.org.uk/downloads/concealedcables.pdf
• IEE article
• IEE Article on 17th Edition requirements for concealed cables.

How are you going to be supplying the workshop?

 

[MalcofArabia]

It is frowned upon now to notch or cut joists and noggins as it can weaken them. It is recommended that you drill holes through them to run cables.

What you can do is before you fit the insulation run your cables to the positions fit your noggins as I'm assuming as you are running flush and be fitting back boxes. If your fitting plaster board boxes then just site the cables.

You can then cut the insulation from the floor to the cable. Then cut another piece from the cable to the ceiling. Then you will have to cut out all the boxes.............what a chew.

BaS is right run it surface in a commercial enviroment. If you run it flush you will have to think about fitting RCD's if you don't bury it deep enough if you don't cover with earth metal conduit etc etc. Then you will have rating factors on the cable for being in 100mm insulation. Though not to much of a concern on small cable, but as you go over 4mm it can be quite restrictive.

There are so many neat trunkings you can use for power, data cables etc that are segregated and nest accessories.

 

[ban-all-sheds]

Malc raises a point I hadn't picked up on - if you're lining the walls with plywood, what sort of accessory boxes do you plan to use, and fixed to what and how?

 

[meb97me]

i was hoping to keep the insulation as thick as possible to help retain the heat as i'll probably be in there most eveings so anything that helps it keep warm is a plus

The wokshop is just for my tinkering not a commerical one.

The workshop has had armoured cable run to it buried underground. Its run from a 32amp (iirc - rating was checked but cant remember exactly what it is) breaker from the house consumer unit and i have a seperate consumer unit for the workshop. This will comprise of a ring main for the wall plug sockets, a seperate 16amp circuit for my welder and another 16amp circuit for my compressor as well as as a lighting circuit. All are RCD protected and the consumer unit has a MCB.

I'm think off the top of my head the cabling i'm using is 2.5mm T+E for all the circuits

I'm using metal surface mounted sockets like these as they'll hopefully stand up to knocks and bangs a bit better i hope than the plastic ones

I've placed noggins in the appropriate positions i want the sockets mounting along the walls

but i'd really like to avoid the added expense of additonal trunking if possible

i'm thinking i may just have to cut a channel out of the kinspan where teh cable goes across from joist to joist for it to run through as suggested. A bit more labour intesive but cheaper

 

[ban-all-sheds]

Have you allowed for the cost of notification?

 

[meb97me]

yep

but cheers for the link