I'm trying to work on a simple circuit where (simplified) I plug in a 240V 50Hz AC through a resistive coil to convert to heat. The coil is insulated and placed under a metal plate. I'm noticing that if I touch the plate, I would feel a slight buzzing/tingling sensation, AKA touch current. I have some questions about that:
Is this effect due to induction, or is it a capacitance phenomenon, (or something else??)
How should I design to ground the plate to eliminate/reduce the touch current? It's easy with 3-pronged plugs with a dedicated earth pin, but old EU plugs are round two-prong and indiscriminately reversible making grounding tricky. The solution would have to work when I plug it in either direction.