Greetings to everyone.

I need some advice from experienced electricians please.

A 15m electrical cable (underground) needs to be connected from an existing DB to a mini sub DB (63A earth leakage,20A breakers x2 and 10A light circuit)

On mini sub DB there are 2 plug points, 1 x 2ft double fluorescent light.... 9000btu aircon will be installed on later stage using one of the 20A breakers.

This place is just a storeroom nothing will be connected on the plugs.

My question is what cable size and 'outt building' breaker would be sufficient for this installation?