Cables under insulation (above slab)

[WWilts]

Builder thinks cables under insulation (above slab) will work fine and be more cost-effective than ducting under slab, lintels etc. Idea is to get the cables to a central room.
 

Any reason to avoid that plan?

 

Cables =
SWA for 3 phase supply from external kiosk to inside house,
Telecom cable (probably fibre 2 core)
Data cable

- - - - 

found this on google:

https://forum.ovoenergy.com/your-smart-home-139/house-insulation-electricity-cables-and-fire-risk-the-good-and-the-bad-7367

Seems it's a really bad idea to surround electrical cables with insulation, owing to risk of overheating and fire

Edited August 25, 2021 by WWilts
added info re fire risk

[Russell griffiths]

Duct under the slab, how would you pull a new cable in if you surround it in insulation and screed over it. 

Unless you duct it there as well, don’t underestimate how many cable ducts you will have coming in and out. 

I think I have something like 5 electrical ducts up to my plant cupboard. 

1 in and 4 out to feed things in the garden.