Running 4 CLU048-1212's wired in series, ~144v/~200w, sounds like a bad idea on these, yes? I can't post links but it seems like where you can find ratings for these things (digikey, not really the amazon/ebay listings) it's typically 12v 5a. They do accept thick wire, but whatever is inside sounds like the weak link.
At 3:07 growmau5 is using the same connectors I have for a high voltage setup but doesn't mention any voltage/current concerns.. I use them for 12v applications like my heat sink fans, and ~20v low current solar applications, but for connecting remote drivers to my fixture it seems a little... sketch?