Hey there datcope, We have seen homeowners mount transformers in sheds before. For this application, you would need to have an adequate power source in the shed and make sure that the transformer was safely mounted to a firm surface with a foot of clearance in all directions. As far as an attic goes, myself and the team here would recommend against this. For starters, our transformers are designed and certified for outdoor uses. For second story lighting, you can always invest in a bit more cable if needed and run wire up, down, and along gutters.
