I have an Engineering BASc and went on to do an MA and then PhD in Philosophy winning major Canadian and provincial scholarships.
Universities varied widely in how they interpreted their requirements for how many additional courses or years of study I would need for admittance to their MA programs. Some variation was likely due to the discretion of graduate admissions officers. It helped significantly that I had excellent marks, since one of the common admittance criteria is evidence that you will succeed as a graduate student.
I had taken a number of philosophy courses part-time after graduating, and got excellent marks. Several universities wanted me to start in second or third year in a second bachelor's program and then complete it in order to meet their requirement of a BA majoring in the discipline. One was willing to provisionally admit me once my total accumulated credits in philosophy amounted to the equivalent of those required for a double-major in philosophy (and another subject), which was their normal minimum requirement for background in the discipline. This allowed me to start after just 8 months in a specially designed qualifying program.
I don't think a Certificate is useful for entrance into a Master's. The courses themselves, how you do in them, and the reputation of the institution where you take them is more important.