Cables in conduits do not need to be derated as long as (1) there is only one cable in the conduit (2) the conduit is not buried in insulation (and is not excessively long)
Yes it would be better to have a separate 20A circuit for the oven in 2.5mm T&E. this will be just adequate for a double oven should you buy one in future. if you use 6mm or even 10mm it will give you the option to use it for a hob or cooker next time you change the layout of your kitchen; but it will be more difficult to connect and you will need deeper back-boxes.
A part p electrician (one who is a member of a self-certification scheme and will issue the documentation) should install and test the whole circuit, not just connect it at the CU. However if you do all the chasing and fix the backboxes this should make his job much easier and quicker, and therefore cheaper. If you run or connect the cables he cannot sign it off as his own work, and cannot be sure that you haven't nicked one, or put a nail through it, or wrapped a hidden joint in insulation tape and plastered over it.
p.s. OOI, see if you can find out what is the recommendation of thickness of insulation; and if you need a dense one for noise absorbtion.
Yes it would be better to have a separate 20A circuit for the oven in 2.5mm T&E. this will be just adequate for a double oven should you buy one in future. if you use 6mm or even 10mm it will give you the option to use it for a hob or cooker next time you change the layout of your kitchen; but it will be more difficult to connect and you will need deeper back-boxes.
A part p electrician (one who is a member of a self-certification scheme and will issue the documentation) should install and test the whole circuit, not just connect it at the CU. However if you do all the chasing and fix the backboxes this should make his job much easier and quicker, and therefore cheaper. If you run or connect the cables he cannot sign it off as his own work, and cannot be sure that you haven't nicked one, or put a nail through it, or wrapped a hidden joint in insulation tape and plastered over it.
p.s. OOI, see if you can find out what is the recommendation of thickness of insulation; and if you need a dense one for noise absorbtion.
