Is there a law that says employers must prevent employee burnout? No, not really, but occupational health and safety legislation across Canada provides that an employer must take every precaution reasonable in the circumstances to protect a worker. That could include ensuring that an employee does not suffer from full blown burnout. When employers assist in this regard, they are also ensuring that their workplaces remain healthy and productive, and have higher morale.
Have you ever had a vacation that was just long enough? At the end of a week off, have you ever thought, "That was perfect, and now I can't wait to get back to work"?