You need a Certificate of Qualification to work in some trades in Canada. Each trade has different certification requirements.
"In Canada, provinces and territories are in charge of education and training. ... To get a certificate of qualification, the regulatory body that governs trades in a province or territory must assess your training, trade experience and skills to decide if you are eligible to write an exam to be certified."
cic.gc.ca/english/helpcentre/answer.asp?qnum=743&top=29
