I am constructing a gazebo on my flat roof deck out of 2" galvanized metal pipes and joints. I would like to attach a light fixture on one of the upper pipes. Can I pull electrical through the galvanized structure itself treating it as a large conduit? If so, at any point do I need to attach grounding screws or take any other measure to ensure I am following proper electrical practices? I am obtaining power through a plastic conduit protruding out of the roof which will feed directly in through the bottom of one of the riser posts.
Thanks in advance.