Most people don't know this but the standard 30 amp power cord as a designed in safety factor and will handle 50amp draw just fine.
Good luck!
In the marine environment, with the crappy twist lock plugs we use here in the US, you are lucky to get even 30A out of a 30A rated cable.
The receptacle at the boat, cord, cord, and pedestal are a HUGE source of corrosion and thus resistance making passing even 30A, on a slightly used 30A cable or dock receptacle, more than a few months old, a dubious task at best.. We then often add multiple adapters, Y's, splitters, converters etc. etc. adding even more friction fit connections to potentially fail.
I see LOTS of burned 30A and 50A cord-sets that never tripped a breaker but the resulting high resistance has melted the plug end or receptacle end.. While 10GA wire can handle 50A for a short period it will eventually over heat if asked to do so for long periods, especially with a long cable and it simply should not be done. That said the fire would most likely occur at the receptacle before the wire as that is the real weak link in the US shore power system. These cord sets are also tightly bundled in a jacket that does not dissipate heat well making their over all ampacity ratings considerably lower than that of a single bare non-bundled conductor of 10GA wire.
Trying to pull more than 30A through a 30A cable will almost always result in issues unless you are in the controlled environment of UL Lab's, testing brand new everything...
Once at the dock nothing is new, or performs at "new" for very long...
Please do not try and pull more than 30A through a 30A shore power cord set. If you light up the marina it will likely exceed the coverage of your insurance policy, and you'll be on the hook. Heck for that matter try not to pull much more than 25A and you'll be doing far better than pushing the cable to its face value rating..... In a house it is one thing but boats are not indoors, the connections corrode, oxidize and cause high resistance which leads to heat and eventually fire even at well below the cord sets face value rating.
The cord set below had the "potential" to draw about 42A on this boat. According to the owner it never drew more than about 36A - 38A. This is the reality of the marine environment hard at work when combined with the crappy shore power standard we use here.
This could have burned down the entire marina. When I showed up at this boat it was drawing about 22A and the temp on this was over 185F.... It had clearly been much hotter....
Please inspect and clean your plugs and receptacle tips often!!! Sadly these are not rare instances...
