Electrical Wiring in the Home/wiring garage
i have an RV hooked to a 30 amp power source on the meter box, there is still a 50 amp plug in left at the box, can run a cord like the RV has to a storage shed breaker box, and can that 50 amp cord be reduced to a 30 amp cord?
I don't know what your "cord like the RV has" looks like.
If it is a cord like an extension cord then the answer is no.
From the meter to another breaker box it has to be hard-wired and the neutral and ground have to be isolated.
The wire size has to be large enough to accommodate the breaker. So if you want to run #10 awg wire you would need to change the breaker to a 30 amp.
If you keep the 50 amp breaker with smaller wire then you run the risk of creating a fire or destroying equipment.
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here