Don't know what you're working on but you may find a plastic or metal channel (U-shaped conduit) on the underside of the column that the wires run through. Remove it.

Once removed, bend the wires at the connector so that connector can be run up lengthwise through the collars of the upper column. It's a snug fit but it will go through there. Installation is the reverse.

In the image below the column is upside down. Screwdriver is pointing to one of the screws that hold (in this case, metal) the cover on.