This is neat diagram of how the CAMPGROUND PEDESTALs are wired.
The 30AMP is wired just like a standard 120VAC RECEPTACLE but has larger wiring and is fed by a 30AMP breaker in the panel.
As long as your 30AMP SERVICE lash-up tests out like shown here you will be fine...
Home wiring LASH-UPS are best done by brother-in-laws and friends. Then when you blow up your friends trailer appliances you only end up with a fist fight. If you have a qualified electrician wire up it then he will be bonded and if he blows up your friends appliances then his insurance will pay for it... Tread lightly...
Roy Ken