I have just finished building the ELV PPS5330 PSU kit which is both accurate and very solid. BUT… It uses a two-core flex to the unit that goes straight onto an input board. There is a type X2 capacitor across the transformer which comes from the two holes in the PCB held down by cable ties. The double pole mains switch is insulated and fused by a shrouded pcb mounted fuse. The board is held in two places with plenty of clearance from the base panel which has an insulated shield on it.
All this means is the steel case is unearthed. It is coated in a thick layer of quality paint, but it is still steel. There is a spade terminal internally for an earth lug. Is this safe? Should I put a ground lug on the back of the case and bond it to my power ground? Clearances and isolation are both substantial.