De-rating of bunched cables

[bernardgreen]

I need to find an idiots guide to the derating needed when PVC cables are bunched in plastic ducting ( 90mm x 40mm internal ).

These are rising from consumer unit into ceiling space on a wall that cannot be channelled.

Also what is the recommended height for a consumer unit.

Conversion and re-wire being planned for a large house.

Bernard
Sharnbrook

 

[davy_owen_88]

An ideal height for a consumer unit is one where it can be easily reached by an adult, but where its too high for young children to poke around. I don't believe there is a min/max height in the regs, so just go where its safe and convenient.

Regarding the conduit question - heres a useful link that should tell you all you need:
http://www.tlc-direct.co.uk/Book/4.5.3.htm

Note that the grouping factors still apply. It might work out better for you to split them into 2 bunches.