The 3A300 has been designed to integrate a complete scheme allowing bi-directional group intertripping of up to four remotely connected sites. Inherent 5KV or 15KV isolation allows application on electrical networks where large induced voltages may be experienced on the pilots. System reliability is provided by the extensive built in supervision facilities. Security is achieved through the high isolation & AC immunity of the intertrip receive elements. The efficient compact design of the 3A300 makes it suitable for surface or panel mounting & allows the use of standard sub station batteries.