Regulation s. 186 (f) does not specify the number of hours per week.  Thus, the student can work "as many hours" on campus as needed provided the student is a full time student as defined by the educational institution and is studying in an academic, professional or vocational program. 
 

Exclusion:

 the student who is studying English or French as a second language is not allowed to work on-campus or off-campus.   
 

EXCEPTION:

  if the student is a studying full-time academic program and also studying English as part of it, the student can work on or off-campus as per Program Delivery Instructions (PDI) exemption.
 

NOTE:

  The study permit must have to have a remark "May be eligible to work on or off campus if meets R 186 (f) or (v) or (u).

Typically:  The students who are studying English or French as a second language would not have the remark to work on or off-campus.

• Reference 1
• Reference 2