As above above,noticed this on a job where a 30A and 5amp wylex fuses fed 2 rcbos with a 6mm cable and 1.5mm cables

to the rcbs.Think it was done because of little space next to the cu for dp devices.Is there anything wrong with this approach

appart from having   overload protection in series?

                                                                                                       Thanks,

                                                                                                               Hz