metal trunking

tp25

where can I get cheap metal trunking? it's for domestic retrofit application.

I need to use these to run the electric cables between the joists.

2011

Kellighers or Eurosales, both in Sandyford industrial estate.

Eurosales will deliver free, unsure about Kellighers.
Unusual to install it in a domestic installation, but not unheard of.
Don't forget to earth it.

Plastic trunking may be a better option.

tp25

the application I want to use it for is rather strange, I didn't have another idea, I don't want to re-wire whole house just to lift the cables above the insulation, I think to slide the trunking below the insulation (whole way to the external wall)

I need to deal with this problem (picture attached)

2011

Is your intension to fix the trunking to the top of the joists ?

tp25

my problem is that builder did run the cables on the top of foil backed plasterboard (as seen on the picture), the cables are tight, then he covered cables with 200mm of moywool on the top (this was back in 2004/2005).
I want to separate the cables from insulation, I don't want to re-wire the cables at this stage. I don't want to completely remove insulation either.

fixing to the top of joists would require to re-wire cables. Re-wire cables sounds like major works, I wonder if these can be joined to the longer bits (this might be doable).

If I need to re-wire new each new cable from the box to the roof that sounds like too big for the moment..

2011

tp25 wrote: »

my problem is that builder did run the cables on the top of foil backed plasterboard (as seen on the picture), the cables are tight,

How tight? No slack at all?
Tight is not good.
The installation of trunking may make them tighter.

then he covered cables with 200mm of moywool on the top (this was back in 2004/2005).

Covering cables with insulation would not concern me.
Covering transformers or making junction boxes inaccessible would.

I want to separate the cables from insulation

Why?

I don't want to completely remove insulation either.

If you want to use trunking I think plastic would be better.

If you just want a cable support you could consider cable tray (plastic is also an option for this).

tp25

2011 wrote: »

How tight? No slack at all?
Tight is not good.

little tight, little slack but not enough to lift cables above the insulation.

2011 wrote: »

Covering cables with insulation would not concern me.

Why?

I plan to use 18mm osb over the joists, I am not comfortable with cables sleeping under the insulation. It may get warm there.

I'm adding new insulation to the roof.

tp25

thanks for suggesting cable tray! this is what I meant, I just couldn't name it! - but again, I'm not sure if this is advisable for this application.

tp25

2011 wrote: »

If you just want a cable support you could consider cable tray (plastic is also an option for this).

it's not for the support, I'm just thinking to separate cables (which may get hot) from the insulation.

2011

tp25 wrote: »

little tight, little slack but not enough to lift cables above the insulation.

I would leave them so. If the trunking causes strain at the terminals you will be in a worse place.

I plan to use 18mm osb over the joists, I am not comfortable with cables sleeping under the insulation. It may get warm there.

Not bring smart, but if they get warm they are most probebly undersized. It is normal in donestic installations to have cables under floorboards and under insulation.

My advice is to leave it.

tomdempsey200

ya

leave them alone...not worth the bother

hufpc8w3adnk65

And you want too move the cables WHY?

Bruthal

The idea seems to have been to contain cables inside trunking to avoid covering them directly with insulation.

Completely unnecessary.

hufpc8w3adnk65

Bruthal wrote: »

The idea seems to have been to contain cables inside trunking to avoid covering them directly with insulation.

Completely unnecessary.

Agreed the notion of joining cables twice too extended them too be long enough too sit in the metal trunking is mental also!

Andrew_Doran

In fairness to the OP the insulation manufacturers tend to recommend that cables are not buried (ass covering perhaps).

Tuco88

Just to point out with the Insulation, It's Polystyrene that attack's the Plasticiser in PVC cables, the white stuff on the back of the Insulated slabs. That foil back solid stuff is usually Polyurethane (King Span) that's fine. It's just that I remember a while back a fellow was wiring his own house, Used 50 x 50 PVC trunking all over the place, I thought he was just being really,really picky.... Until I spotted the 20mm conduit for the lights too, He also was unaware until another lad said the same to him. Suffered alot of hardship....

Mind you I have seen steel trunking using in an attic before, straight run down the running board earthed and all, Nothing wrong with it good idea imo, If your later converting or using it alot.