Hi
I have a built in microwave fed via a 2.5mm T&E cable which is to be chased into the wall and feed from a switched FCU up to a unswitched socket inside an overhead cupboard. The socket is to be directly above the microwave oven.
Equally, I have a 1.0mm T&E cable that needs to get to the top of the same cupboard and ultimately feed an LED transformer for under cupboard lighting.
All cables rise from the same location, but the 1.0mm T&E passes by the FCU until it reaches the top of the cupboards.
All cable share the same wall chase.
Question is... Does the 1.0mm cable pass through the 25mm deep metal box keeping it as close to the top and bottom and back of the box - As per "A" in the drawing  Or should it detour around the outside of the box as per "B"?  
Unless nether are correct??

I'd go for A