but that would mean there no insulation in the property, and most if not all new builds have insulation in them so i can't see how it would b ref method c
Rather than derating it's generally better to avoid the insulation! No reason why in almost all cases you shouldn't be able to prevent it being a factor.
If you have 400mm of 2/2 trunking fitted vertically where it passes through the insulation you really dont need to apply methods related to cable in trunking.... the trunking is open top and several orders larger than the cable so any thermal dissipation restrictions will be neglegible and clipped direct can be used as normal.
Best EV Chargers by Electrical2Go! The official electric vehicle charger supplier.
OFFICIAL SPONSORS
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc