Garage cable mounting

[tom6]

Hi All,

Looking for some confirmation / advice.

I have recently built a garage and will be getting it wired shortly, it is of timber frame construction and timber cladding outside and will have kingspan insulation with plasterboard finish inside with all joints taped and plastered.

Is it ok for all cables to be mounted behind the kingspan insulation obviously supported with clips where required. All the cabling will be ran in the loft and just dropped down the wall for sockets & light switches

Many thanks

 

[telectrix]

you'd need to derate your cables by 50%. eg. 2.5mm will be down to 13A. personally, i'd do the drops surface in mini-trunking or pvc conduit and use surface boxes.

 

[tom6]

Perfect thanks for the clarification, will go with the PVC conduit drops.

 

[telectrix]

i would use the shatterproof boxes with 20mm knockouts, and with adaptors on the conduit. makes a neat job.

 

[ChrisElectrical88]

i would use the shatterproof boxes with 20mm knockouts, and with adaptors on the conduit. makes a neat job.

I would use galv conduit, makes it even neater

 

[Dizzy_Maskell]

i would use the shatterproof boxes with 20mm knockouts, and with adaptors on the conduit. makes a neat job.

I would use galv conduit, makes it even neater

Id go full swa with metal glad fixings cable tray and drop in a linked out three phase board to power it!!!!!!!

 

[ChrisElectrical88]

Id go full swa with metal glad fixings cable tray and drop in a linked out three phase board to power it!!!!!!!

High bay lighting installed and get a roller shutter door put in whilst your at it!

 

[Engineer54]

If this is going to be a bog standard garage, that only needs power for a bit of lighting and the odd power tool on occasions is the derating really going to be an issue?? Could even use 4mm radial(s) if you're that worried.

Trouble with surface work in a domestic garage, is that it collects dust and debris and ends up looking tired over time. Seeing as you're going to the lengths of boarding this garage out, think i'd prefer to see flushed outlets and switches.

 

[Rockingit]

Seeing as you're going to the lengths of boarding this garage out, think i'd prefer to see flushed outlets and switches.

I did a six car garage on a newbuild a while back that had something like a dozen flush sockets, walls plastered, log burner, loft insulated... it was every bit as good and the same size as a bungalow!!

 

[Marvo]

I've moved this to the DIY forum for you Tom.

I'd also add that certain types of styrofoam/polystyrene insulation can cause PVC cable sheath to deteriorate quite rapidly so conduit or trunking may be necessary where contact may occur.

 

[Octopus]

In these such situations the OP should really talk to a sparky or 2 so he can gauge what's best and how much its likely to cost. He hasn't mentioned the supply as yet!

 

[tom6]

Thanks for all the input. I wish i had the size to get high bay lighting!

Its just 6m square. I done electrical engineering at college quite a few years ago so just wanted to check current regulations etc.

The garage supply is a 10mm 3 core SWA of around a 10 metre run to the garage where it will be terminated into the CU. Was planning 1 ring circuit and 1 lighting...(internal lighting & external lighting) All RCD protected of course

Thanks for moving the post - i have heard about the PVC sheath and insulation before would hope to keep the cables away from insulation by clipping in cavity space in wall.

Originally wanted flush fitting accessories since i am sheeting it up but the conduit seems like it will be tidy if done neatly!

 

[tom6]

Thanks for all the input. I wish i had the size to get high bay lighting!

Its just 6m square. I done electrical engineering at college quite a few years ago so just wanted to check current regulations etc.

The garage supply is a 10mm 3 core SWA of around a 10 metre run to the garage where it will be terminated into the CU. Was planning 1 ring circuit and 1 lighting...(internal lighting & external lighting) All RCD protected of course

Thanks for moving the post - i have heard about the PVC sheath and insulation before would hope to keep the cables away from insulation by clipping in cavity space in wall.

Originally wanted flush fitting accessories since i am sheeting it up but the conduit seems like it will be tidy if done neatly!

I meant 2 lighting circuits! One for outside one for inside.

 

[Des 56]

In these such situations the OP should really talk to a sparky or 2 so he can gauge what's best and how much its likely to cost. He hasn't mentioned the supply as yet!

It would seem that it is going to be a in house installation,there has been no mention of a spark involved,if there was,I believe the questions and responses seem too detailed for just an inquisitive client
Perhaps installation methods and calculations will be posted by a n other very shortly

quote eng54
Trouble with surface work in a domestic garage, is that it collects dust and debris and ends up looking tired over time.

Too right,damage is also more likely and possibly would need more consideration then

 

[Octopus]

It would seem that it is going to be a in house installation,there has been no mention of a spark involved,if there was,I believe the questions and responses seem too detailed for just an inquisitive client
Perhaps installation methods and calculations will be posted by a n other very shortly

quote eng54
Trouble with surface work in a domestic garage, is that it collects dust and debris and ends up looking tired over time.

Too right,damage is also more likely and possibly would need more consideration then

In which case I would recommend no further advice for the OP.

 

[Engineer54]

I've moved this to the DIY forum for you Tom.

I'd also add that certain types of styrofoam/polystyrene insulation can cause PVC cable sheath to deteriorate quite rapidly so conduit or trunking may be necessary where contact may occur.

That's a thing of the past now Marvo, all of the insulation types available now, do not have the chemical makeup to cause plasticising of PVC cable sheaths etc....