You could use the spa panel and feed the the 50 amp gfi breaker the by a two pole 20 you can get the spa panels with extra breaker spaces. Then you are gfi protect in all other circuits on that panel.
It probably has a fuse inside of it but the wire inside are so small if there is a fault the will all fuse together from the plug point to the fuse if it has a fuse it might have a thermal cut out instead.