While I am not going to try and "guess" or "reference" code, common sense says you need it protected by GFCI protection.
My setup was similar. I wired a P300 transformer for my landscaping lights. It was plugged directly into the the pad mounted GFCI outlet, running off a dummy timer. I finally wanted it controlled via the automation system (ET4). So I wired it into its own relay and added a GFCI breaker.