wiring and loft insulation

[Barney78]

I know that its not acceptable to run cables under loft insulation, but would it be acceptable to run it through trunking stuck to the sides of the joists?

 

[ninebob]

Need more information...

What's the rating of the circuit?
What's the size of the cable?
What's the length of the cable run?
Will the trunking be under the insulation?

 

[Barney78]

Its a lighting circuit running off a 5 Amp fuse.
The cable is mostly 1mm twin and earth, although there is some three core and earth for some double switched circuits.
The longest unbroken run of cable will be about 3.5 metres.
Yes the trunking will be covered by the insulation as i was wanting to run it along the sides of the joists so i could board the loft.

 

[ninebob]

What you are proposing sounds fine for cable runs of that type, though personally I would uprate to 1.5mm cable.

Trunking or conduit should have a spacing factor of 45%, ie not more than 45% of the internal area should be occupied by cable, so the size of trunking needs to be approx twice as big (internally) as the cable(s) you intend to run in it.

I'm not a pro spark, so whilst I'm pretty certain that what I've said is correct, it would be useful if one of the really knowledgable guys on here like FWL_Engineer could just confirm it...