Factory calibrated pressure switch utilizes a snap-acting stainless steel diaphragm that reverses its curvature when pressurized to a customer specified actuation pressure. When the disc snaps it opens or closes a set of electrical contacts by means of a transfer pin. Resetting the switch occurs automatically when pressure drops below the release value. The unique latching mechanism in this assures safe electrical cutout even if the reset button is held fully depressed. It also prevents the consumer from restarting the equipment until the line pressure has dropped below the release setpoint.