I ran 10/2 wire from 30amp breaker installed on my house 100amp panel 50’ to my shed . I bought a sub panel as shown below ! Looks like to power the capable 2 breakers I should have ran 10/3 wire ! I am not in need of 220 v so Since the 10/2 is already there can I jump from black power line to other post on box ? I don’t think the single black at present powers both breakers ? I will be using a 15 and a 20amp breaker for outlets and lights .