Citel ds98 400 compact single phase 230v surge protector citel ds98 400 p the citel ds98 400 ac surge protector is used for the secondary protection of single phase networks against surge voltages created by lightning it must be installed close to the equipment to be protected downstream from a primary surge protector p p the ds98 400 is equipped with an internal thermal safety device which will disconnect the unit from the ac network in case of end of life this disconnection is in