When I transcode a compound clip, am I just transcoding the source the clip was taken from?

I have 30 video clips encoded in H.264, each one roughly an hour or so in length. I loaded them all into FCPX, rendered but not transcoded. I extracted a handful of 1-3 minute compound clips from each clip, then removed the source clips from the event browser. I then transcoded just the compound clips in the hopes that just those selections would be transcoded. Trouble is, it looks like FCPX transcoded the source clips, as they all appear in the Transcoded Media folder. My question is: Is there a way to have just the clips I want to use transcoded without having the transcoded source media taking up TBs of space on my hard drive?

Only by exporting the segments you want and reimporting.