[MooseSuite]

Many older parks have outdated power supply equipment that may cause your situation of overloading the circuit. As well if you you are pressing the limit on your 30 amp i.e. a toaster and a heater that will pop the fuse at the pedestal.
You can buy a device that provides the amperage and no ground at the pedestal before you plug in, for safety sake.
A good surge protector will also give you this information and shut down the power if voltage goes too high i.e. 130 or to low 104, as well as ground fault protection.
Progressive Industries makes an excellent surge protection product that you can hard wire or plug into.
Sounds like it is not a trailer issue.

Bon Chance mes amis.