The usual rule of thumb for lack of additional protection by 30mA RCD on domestic sockets is C3 for ones just serving indoor areas, C2 for those serving outdoor areas. Partly that's due to very long extension leads typically used outdoors that can defeat ADS by overcurrent device due to the increased loop impedance aren't reasonably going to be needed indoors, and partly that the machines in unskilled hands that can easily cut through flexes (hedge trimmers, lawn mowers) again aren't to be expected indoors, and outdoors connection with Earth potential is far more likely. For industrial settings, some extra judgement will be needed depending on the exact circumstances. If the floor is reasonably insulated from Earth (usually is via the damp proof membrane) and the workforce reasonably trained, the hazard from the cut flex for example may be quite small - both in terms of likelihood of it occurring and the chances of a serious shock if it does. If sliced flexes are a regular occurrence than there are bigger H&S problems than can be addressed by an RCD (since fatal shocks can be had from L & N). On the other hand some fabrication areas are more like outdoors if with a bit of shelter from the rain. It all depends...

    - Andy.

Thanks Andy

Thanks Andy