I cannot find clear information on running mains and low voltage on adjacent layers on FR4 PCBs. I understand how much creepage distance to allow, but for example, can I run - 50Vdc, 240Vac, 0Vac, ground, on a 4 layer 1.6mm FR4 PCB. Would it be more appropriate to use a 6layer pcb, leaving blank layers between 50V/240Vac/0Vac?
Could someone point me to a standard on this? I have had not much luck with Kervill's Low Voltage Directive.