breaking point

noun2

1. •
   The point at which the increasing strain in a material causes it to break.
2. •
   (figurative) The point at which a person or system succumbs to stresses or pressures and descends into crisis.

   • Even before Hurricane Sandy, New York was sheltering more homeless people than any city in the United States: a record 47,000 women, men and children, in a system strained to the breaking point. — 2012