The normal Summer courses load limit for undergraduate student is 2.0 credits and no more than the equivalent of three half-credits in either the Early Summer or Late Summer period.(Deferred and audit courses are included in calculating the courses load.) A student may exceed his limit to maximum of 3.0 credits only with permission of the Registrar's Office, 200 Tory Building.
I went there last week regarding the overload, they haven't started dealing with Summer Overload application yet. Good luck!