Patents Assigned to 3-M Company
  • Electric circuit breaker with ground fault protection
    Patent number: 4000444
    Abstract: Electric circuit breaker including highly sensitive ground fault responsive means for protecting human life from electrical shock. The circuit breaker is suitable for mounting in a panelboard at the service entrance of a building to provide ground fault protection for the individual branch circuits in the building.
    Type: Grant
    Filed: March 12, 1973
    Date of Patent: December 28, 1976
    Assignee: 3-M Company
    Inventors: Ellwood S. Douglas, Richard C. Doyle, David William Nestor, Wallace W. Wahlgren