Last week I came across two different transformer pads with a considerable amount of mud and mulch piled about 2-3 inches above the pad and around the cover.
I didn't have the cover removed and there were no other readily apparent problems with the installation.
However, typically, I find that outside transformers are fairly well mounted and clear of debris. This was a little unusual (at least for me) and while it didn't look quite right, I can't find anything that prohibits a transformer mounted on a pad from having mulch, dirt, or other material piled up around the cover.
I couldn't find anything in Article 450. Anyone aware of any requirement along this line?