Oil Boiler cable size

[Spoon]

I may have misunderstood the OP but I think the SFCU is in the airing cupboard with the rest of the boiler controls and wiring Centre and the cable in question is just the cable going to the boiler in the outbuilding

You could be right mate.

OP: Any change of clarification on this set-up please.

 

[buzz30]

They’ve fitted a new 3amp spur next to the immersion fused spur in the airing cupboard that’s where the programmer pump etc are then run the boiler cable under the floors down the wall in the pantry to outside junction box armored cable to another junction box then the cable runs in trunking in the outhouse to the boiler. Think his thought was the armored cable is going under a flower bed was better protection than a cable in a duct

 

[Dave OCD]

It actually sounds ok to me.