I am planning to run a power to the garage from a 16 amps RDC from house CU in a new build. I want a power a twin socket, an internal light, and a floodlight. There is a power feed to a junction box on the outside of the house from a CU. My plan is to install a power supply as per the attached sketch. I will call an electrician to connect and test the system. Planning not to have CU in the garage as i will not need any more supply and want to keep the cost down. Any advice will be useful and how much an electrician would charge to connect and test?