Be sure the electrical knows he/she is to wire a 30TT 30 amp 120 volt receptacle, not a 30 amp 220 volt receptacle. It would be good to download and print out information on NEMA 30TT receptacles and give it to your electrician.
I think that information is in the FROG forum library. Maybe someone can post a link to it. I can't with my phone.
2011 Sunseeker 3100
1997 Pathfinder Toad