I have a detached building at the property I just purchased. There is 2/2/4 URD (3 wire aluminum about 75′ in length) cable pulled from the main panel at the house to the detached building already but is not terminated on either end yet. Is it ok to just have the 2 hots and neutral and install a ground rod at the sub panel or should I use only one of the hot wires and make the other a neutral and the intended neutral as a ground wire coming from the main panel? I know doing this will inhibit my ability to have 240v at the sub panel but I will never use anything except 120v as all I will have in the detached building is 3 lights and 2 duplex receptacles. Thanks in advance!