Hi,
Here's the info "The cumulative duration regulation establishes a maximum allowable duration of four years that a temporary foreign worker can work in Canada, followed by a period of four years in which the worker would not be eligible to work in Canada. It takes effect April 1, 2011 for all TFWs; therefore, the earliest date that a TFW could reach the four-year cumulative duration is April 1, 2015."
However the 4 years doesn't apply to NOC A or O or the following:
Exceptions
The four-year cumulative duration will not apply to TFWs entering under one of the following occupations:
TFWs seeking to work in managerial (NOC 0) or professional occupational (NOC A);
TFWs who have applied for permanent residence and have received:
a Certificat de sélection du Québec (CSQ) if applying as a Quebec Skilled Worker;
a Provincial Nominee Program (PNP) certificate if applying as a provincial nominee;
an approval in principle letter if applying under the Live-in Caregiver Class;
a positive selection decision if applying under the Federal Skilled Worker Class;
a positive selection decision if applying under the Canadian Experience Class;
TFWs who are employed in Canada under an international agreement, such as NAFTA, the Seasonal Agricultural Worker Program, or another agreement;
TFWs who are exempt from the Labour Market Opinion process, including
Spouses and common-law partners of highly skilled TFWS;
Charitable or religious workers;
Entrepreneurs, intra-company transferees, researchers and academics;
Others for purposes of self-support (refugee claimants) or humanitarian reasons (destitute students, holders of Temporary Resident Permits valid for at least six months).