Off campusのバイトなら、20時間/週以下(アカデミック期間;9月から5月?)。それ以外(夏休み期間)は時間制限なしで、フルタイムで働けます。
To work off campus, you must apply for a work permit. Do not begin to work off campus until you have received your work permit. The work permit authorizes you to work up to 20 hours per week during regular academic sessions, and full time during scheduled breaks (for example, winter and summer holidays, and spring break).