Can the Fronius Rapid Shutdown Box Quattro or Duo be used with a Fronius Symo 3phase inverter?

Yes, generally the Fronius Rapid Shutdown boxes can be used. However, the Quattro and Duo rapid shutdown boxes are only certified up to 600Vdc.

Stringing of the solar array will be affected and only 600Voc compatible designs are possible. This might affect the maximum output power and compatibility to specifically larger inverter power classes. We do not recommend this operation.