Jeepmudman:

First off, welcome to ECN! [Linked Image]

Plexi might be o.k., certainly a better insulator than wood, but if I was the AHJ, I'd still fail it. Plexi is sensitive to temperature and would readily deform/melt if the lugs got too warm. Now as to a plexi cover that would be o.k. as long as it was not in direct contact with the lugs.

In general:

An issue that I have now noticed and no one's questioned: Aren't the parallel conductors all supposed to be the same length? (Not only each phase/neutral, but the overall set.) From the looks of this install, I'd say no. Another red sticker?

It also makes no economic sense either, for if the panel is just the opposite side of this cabinet, wouldn't a single run of the proper conductor size cost less than the two runs installed? [Linked Image]

Stupid should be painful.