The Conduit box has several openings. However, the conduit box only communicates with the PDP through the large rectangular opening on the top of it. The circular conduit box openings are meant for the connections when you have multiple XW inverters.
Here is an image that depicts the mismatch of the circular openings for the conduit and the PDP
Here is a picture of the correct way to communicate between the XW PDP and the conduit box.