The coupling device AGH520S is designed to extend the nominal voltage range of the ISOMETER® iso685… series and IRDH275-4…/IRDH375-4…/IR470LY-40/IR420-D6/IRDH1065B-4 to (3)AC 0…7200 V,
50…400 Hz. The coupling device is connected to the system to be monitored by one pole and connected to the terminal AK of the ISOMETER® by means of the terminal 5.