3036 fuses feeding rcbos in enclosure.

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

  • Hi Hz, I often see this arrangement In hospitals, for example within surgical theatres where modifications have been implemented, it is common to encounter electrical arrangements where new circuits are safeguarded by RCBOs that are, in turn, backed up by the existing BS 88-C fuses. In my opinion, provided that adequate overcurrent protection measures are established and maintained, such configurations should not present any issues.

  • Seems reasonable to me - in many ways better than feeding an RCBO from an MCB (of whatever rating) as there's a somewhat better chance of discrimination. CU replacement isn't a mandatory cure-all.

       - Andy.

  • Thanks for the replies,

                     Regards,

                                       Hz