Note that the NEMA TT-30R “RV” receptacle is a angled-blade “crowfoot” style—not to be confused with the 3-blade ‘dryer plug’

Rated 125V 30A 2-pole 3-wire grounded receptacle
http://www.state-elec.com/leviton/d503d.pdf page 6 Leviton part no. 7313